diff --git a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosticCompilerTestFE10TestdataTestGenerated.java b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosticCompilerTestFE10TestdataTestGenerated.java
index 83023bab8c2..37c11ff0e21 100644
--- a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosticCompilerTestFE10TestdataTestGenerated.java
+++ b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosticCompilerTestFE10TestdataTestGenerated.java
@@ -3026,6 +3026,12 @@ public class DiagnosticCompilerTestFE10TestdataTestGenerated extends AbstractDia
                 runTest("compiler/testData/diagnostics/tests/backingField/ValDeferredInitInOpenClassOpenValWarning.kt");
             }
 
+            @Test
+            @TestMetadata("ValWithSetterDeferredInit.kt")
+            public void testValWithSetterDeferredInit() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/backingField/ValWithSetterDeferredInit.kt");
+            }
+
             @Test
             @TestMetadata("VarDeferredInitInFinalClass.kt")
             public void testVarDeferredInitInFinalClass() throws Exception {
diff --git a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated.java b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated.java
index be931873b64..b4df0ff4986 100644
--- a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated.java
+++ b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated.java
@@ -3026,6 +3026,12 @@ public class LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated
                 runTest("compiler/testData/diagnostics/tests/backingField/ValDeferredInitInOpenClassOpenValWarning.kt");
             }
 
+            @Test
+            @TestMetadata("ValWithSetterDeferredInit.kt")
+            public void testValWithSetterDeferredInit() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/backingField/ValWithSetterDeferredInit.kt");
+            }
+
             @Test
             @TestMetadata("VarDeferredInitInFinalClass.kt")
             public void testVarDeferredInitInFinalClass() throws Exception {
diff --git a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirLightTreeOldFrontendDiagnosticsTestGenerated.java b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirLightTreeOldFrontendDiagnosticsTestGenerated.java
index 8025ac4125e..aa821efd015 100644
--- a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirLightTreeOldFrontendDiagnosticsTestGenerated.java
+++ b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirLightTreeOldFrontendDiagnosticsTestGenerated.java
@@ -3026,6 +3026,12 @@ public class FirLightTreeOldFrontendDiagnosticsTestGenerated extends AbstractFir
                 runTest("compiler/testData/diagnostics/tests/backingField/ValDeferredInitInOpenClassOpenValWarning.kt");
             }
 
+            @Test
+            @TestMetadata("ValWithSetterDeferredInit.kt")
+            public void testValWithSetterDeferredInit() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/backingField/ValWithSetterDeferredInit.kt");
+            }
+
             @Test
             @TestMetadata("VarDeferredInitInFinalClass.kt")
             public void testVarDeferredInitInFinalClass() throws Exception {
diff --git a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirPsiOldFrontendDiagnosticsTestGenerated.java b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirPsiOldFrontendDiagnosticsTestGenerated.java
index a5bc56fdd3d..3d968e30d7c 100644
--- a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirPsiOldFrontendDiagnosticsTestGenerated.java
+++ b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirPsiOldFrontendDiagnosticsTestGenerated.java
@@ -3032,6 +3032,12 @@ public class FirPsiOldFrontendDiagnosticsTestGenerated extends AbstractFirPsiDia
                 runTest("compiler/testData/diagnostics/tests/backingField/ValDeferredInitInOpenClassOpenValWarning.kt");
             }
 
+            @Test
+            @TestMetadata("ValWithSetterDeferredInit.kt")
+            public void testValWithSetterDeferredInit() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/backingField/ValWithSetterDeferredInit.kt");
+            }
+
             @Test
             @TestMetadata("VarDeferredInitInFinalClass.kt")
             public void testVarDeferredInitInFinalClass() throws Exception {
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirTopLevelPropertiesChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirTopLevelPropertiesChecker.kt
index d612ba1f7ba..80ccbcbd7c9 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirTopLevelPropertiesChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirTopLevelPropertiesChecker.kt
@@ -201,9 +201,6 @@ private fun reportMustBeInitialized(
         suggestMakingItAbstract -> FirErrors.MUST_BE_INITIALIZED_OR_BE_ABSTRACT
         else -> FirErrors.MUST_BE_INITIALIZED
     }
-    if (isOpenValDeferredInitDeprecationWarning && factory == FirErrors.MUST_BE_INITIALIZED) {
-        error("Not reachable case. We can always suggest making `open val` property `final`")
-    }
     reporter.reportOn(
         propertySource,
         when (isMissedMustBeInitializedDeprecationWarning || isOpenValDeferredInitDeprecationWarning) {
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/DeclarationsChecker.kt b/compiler/frontend/src/org/jetbrains/kotlin/resolve/DeclarationsChecker.kt
index 0336599ffe8..fcf548dec98 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/DeclarationsChecker.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/resolve/DeclarationsChecker.kt
@@ -841,9 +841,6 @@ class DeclarationsChecker(
             suggestMakingItAbstract -> MUST_BE_INITIALIZED_OR_BE_ABSTRACT
             else -> MUST_BE_INITIALIZED
         }
-        if (isOpenValDeferredInitDeprecationWarning && factory == MUST_BE_INITIALIZED) {
-            error("Not reachable case. We can always suggest making `open val` property `final`")
-        }
         trace.report(
             when (isMissedMustBeInitializedDeprecationWarning || isOpenValDeferredInitDeprecationWarning) {
                 true -> factory.deprecationWarning
diff --git a/compiler/testData/diagnostics/tests/backingField/ValWithSetterDeferredInit.kt b/compiler/testData/diagnostics/tests/backingField/ValWithSetterDeferredInit.kt
new file mode 100644
index 00000000000..849f9a2f445
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/backingField/ValWithSetterDeferredInit.kt
@@ -0,0 +1,11 @@
+// FIR_IDENTICAL
+// LANGUAGE: -ProhibitOpenValDeferredInitialization
+// DIAGNOSTICS: -DEBUG_INFO_LEAKING_THIS
+open class A {
+    <!MUST_BE_INITIALIZED_WARNING!>open val c: Int<!>
+        <!VAL_WITH_SETTER!>set(value) {}<!>
+
+    init {
+        c = 1
+    }
+}
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
index effa1b49dd0..832783c9615 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
@@ -3032,6 +3032,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                 runTest("compiler/testData/diagnostics/tests/backingField/ValDeferredInitInOpenClassOpenValWarning.kt");
             }
 
+            @Test
+            @TestMetadata("ValWithSetterDeferredInit.kt")
+            public void testValWithSetterDeferredInit() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/backingField/ValWithSetterDeferredInit.kt");
+            }
+
             @Test
             @TestMetadata("VarDeferredInitInFinalClass.kt")
             public void testVarDeferredInitInFinalClass() throws Exception {