diff --git a/compiler/fir/analysis-tests/tests/org/jetbrains/kotlin/fir/FirOldFrontendDiagnosticsTestWithStdlibGenerated.java b/compiler/fir/analysis-tests/tests/org/jetbrains/kotlin/fir/FirOldFrontendDiagnosticsTestWithStdlibGenerated.java
index 6a879fca6f4..4fad49229c9 100644
--- a/compiler/fir/analysis-tests/tests/org/jetbrains/kotlin/fir/FirOldFrontendDiagnosticsTestWithStdlibGenerated.java
+++ b/compiler/fir/analysis-tests/tests/org/jetbrains/kotlin/fir/FirOldFrontendDiagnosticsTestWithStdlibGenerated.java
@@ -1737,6 +1737,11 @@ public class FirOldFrontendDiagnosticsTestWithStdlibGenerated extends AbstractFi
             runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/kt38179.kt");
         }
 
+        @TestMetadata("kt41430.kt")
+        public void testKt41430() throws Exception {
+            runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/kt41430.kt");
+        }
+
         @TestMetadata("lambdaExpectedType.kt")
         public void testLambdaExpectedType() throws Exception {
             runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/lambdaExpectedType.kt");
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/inference/CoroutineInferenceSession.kt b/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/inference/CoroutineInferenceSession.kt
index c8411eed59b..21ae072392f 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/inference/CoroutineInferenceSession.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/inference/CoroutineInferenceSession.kt
@@ -90,15 +90,9 @@ class CoroutineInferenceSession(
         val dispatchReceiver = resolvedCall.dispatchReceiverArgument
         return when {
             extensionReceiver == null && dispatchReceiver == null -> false
-            extensionReceiver == null -> true
-            extensionReceiver.receiver.stableType.containsStubType() -> resolvedCall.candidateDescriptor.hasBuilderInferenceAnnotation()
-            else -> true
-        }
-    }
-
-    private fun KotlinType.containsNotFixedTypeVariable(storage: ConstraintStorage): Boolean {
-        return this.contains {
-            it.constructor in storage.notFixedTypeVariables
+            dispatchReceiver?.receiver?.stableType?.containsStubType() == true -> true
+            extensionReceiver?.receiver?.stableType?.containsStubType() == true -> resolvedCall.candidateDescriptor.hasBuilderInferenceAnnotation()
+            else -> false
         }
     }
 
diff --git a/compiler/testData/diagnostics/testsWithStdLib/coroutines/kt41430.fir.kt b/compiler/testData/diagnostics/testsWithStdLib/coroutines/kt41430.fir.kt
new file mode 100644
index 00000000000..b69ad21f0c9
--- /dev/null
+++ b/compiler/testData/diagnostics/testsWithStdLib/coroutines/kt41430.fir.kt
@@ -0,0 +1,27 @@
+// ISSUE: KT-41430
+
+class A
+
+fun test_1(list: List<Set<A>>) {
+    list.<!AMBIGUITY!>flatMapTo<!>(mutableSetOf()) { <!UNRESOLVED_REFERENCE!>it<!> }
+}
+
+fun test_2(list: List<Set<A>>) {
+    sequence<A> {
+        <!DEBUG_INFO_EXPRESSION_TYPE("ERROR CLASS: Ambiguity: flatMapTo, [kotlin/collections/flatMapTo, kotlin/collections/flatMapTo]")!>list.<!AMBIGUITY!>flatMapTo<!>(mutableSetOf()) { <!UNRESOLVED_REFERENCE!>it<!> }<!>
+    }
+}
+
+fun test_3(list: List<Set<A>>) {
+    sequence {
+        list.<!AMBIGUITY!>flatMapTo<!>(mutableSetOf()) { <!UNRESOLVED_REFERENCE!>it<!> }
+        yield(A())
+    }
+}
+
+fun test_4(list: List<Set<A>>) {
+    sequence {
+        yield(A())
+        list.<!AMBIGUITY!>flatMapTo<!>(mutableSetOf()) { <!UNRESOLVED_REFERENCE!>it<!> }
+    }
+}
diff --git a/compiler/testData/diagnostics/testsWithStdLib/coroutines/kt41430.kt b/compiler/testData/diagnostics/testsWithStdLib/coroutines/kt41430.kt
new file mode 100644
index 00000000000..668d9990625
--- /dev/null
+++ b/compiler/testData/diagnostics/testsWithStdLib/coroutines/kt41430.kt
@@ -0,0 +1,27 @@
+// ISSUE: KT-41430
+
+class A
+
+fun test_1(list: List<Set<A>>) {
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.collections.MutableSet<A>")!>list.flatMapTo(mutableSetOf()) { it }<!>
+}
+
+fun test_2(list: List<Set<A>>) {
+    sequence<A> {
+        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.collections.MutableSet<A>")!>list.flatMapTo(mutableSetOf()) { it }<!>
+    }
+}
+
+fun test_3(list: List<Set<A>>) {
+    sequence {
+        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.collections.MutableSet<A>")!>list.flatMapTo(mutableSetOf()) { it }<!>
+        yield(A())
+    }
+}
+
+fun test_4(list: List<Set<A>>) {
+    sequence {
+        yield(A())
+        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.collections.MutableSet<A>")!>list.flatMapTo(mutableSetOf()) { it }<!>
+    }
+}
diff --git a/compiler/testData/diagnostics/testsWithStdLib/coroutines/kt41430.txt b/compiler/testData/diagnostics/testsWithStdLib/coroutines/kt41430.txt
new file mode 100644
index 00000000000..c4578897128
--- /dev/null
+++ b/compiler/testData/diagnostics/testsWithStdLib/coroutines/kt41430.txt
@@ -0,0 +1,13 @@
+package
+
+public fun test_1(/*0*/ list: kotlin.collections.List<kotlin.collections.Set<A>>): kotlin.Unit
+public fun test_2(/*0*/ list: kotlin.collections.List<kotlin.collections.Set<A>>): kotlin.Unit
+public fun test_3(/*0*/ list: kotlin.collections.List<kotlin.collections.Set<A>>): kotlin.Unit
+public fun test_4(/*0*/ list: kotlin.collections.List<kotlin.collections.Set<A>>): kotlin.Unit
+
+public final class A {
+    public constructor A()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
diff --git a/compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestWithStdLibGenerated.java b/compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestWithStdLibGenerated.java
index 30c88093144..e4530487dae 100644
--- a/compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestWithStdLibGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestWithStdLibGenerated.java
@@ -1737,6 +1737,11 @@ public class DiagnosticsTestWithStdLibGenerated extends AbstractDiagnosticsTestW
             runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/kt38179.kt");
         }
 
+        @TestMetadata("kt41430.kt")
+        public void testKt41430() throws Exception {
+            runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/kt41430.kt");
+        }
+
         @TestMetadata("lambdaExpectedType.kt")
         public void testLambdaExpectedType() throws Exception {
             runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/lambdaExpectedType.kt");
diff --git a/compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsTestWithStdLibUsingJavacGenerated.java b/compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsTestWithStdLibUsingJavacGenerated.java
index 8e73d997313..1abe51c80ad 100644
--- a/compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsTestWithStdLibUsingJavacGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsTestWithStdLibUsingJavacGenerated.java
@@ -1737,6 +1737,11 @@ public class DiagnosticsTestWithStdLibUsingJavacGenerated extends AbstractDiagno
             runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/kt38179.kt");
         }
 
+        @TestMetadata("kt41430.kt")
+        public void testKt41430() throws Exception {
+            runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/kt41430.kt");
+        }
+
         @TestMetadata("lambdaExpectedType.kt")
         public void testLambdaExpectedType() throws Exception {
             runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/lambdaExpectedType.kt");