diff --git a/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/core/compiler/IProblem.java b/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/core/compiler/IProblem.java
index 3fc0a2bbf8d..6b534474b6f 100644
--- a/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/core/compiler/IProblem.java
+++ b/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/core/compiler/IProblem.java
@@ -2538,7 +2538,9 @@ public interface IProblem {
 	int SealedPermittedTypeOutsideOfPackage = TypeRelated + 1859;
 	/** @since 3.28 */
 	int SealedSealedTypeMissingPermits = TypeRelated + 1860;
-	/** @since 3.28 */
+	/** @since 3.28
+	 * @deprecated problem no longer generated
+	 */
 	int SealedInterfaceIsSealedAndNonSealed = TypeRelated + 1861;
 	/** @since 3.28 */
 	int SealedDisAllowedNonSealedModifierInInterface = TypeRelated + 1862;
diff --git a/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/lookup/SourceTypeBinding.java b/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/lookup/SourceTypeBinding.java
index 703ce2d7d26..d62f5165843 100644
--- a/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/lookup/SourceTypeBinding.java
+++ b/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/lookup/SourceTypeBinding.java
@@ -1119,17 +1119,9 @@ private Map.Entry<TypeReference, ReferenceBinding> getFirstSealedSuperTypeOrInte
 	}
 	return null;
 }
-// TODO: Optimize the multiple loops - defer until the feature becomes standard.
+
 private void checkPermitsInType() {
-//	if (/* this.isRecordDeclaration || */this.isEnum())
-//		return; // handled separately
 	TypeDeclaration typeDecl = this.scope.referenceContext;
-	if (this.isInterface()) {
-		if (isSealed() && isNonSealed()) {
-			this.scope.problemReporter().sealedInterfaceIsSealedAndNonSealed(this, typeDecl);
-			return;
-		}
-	}
 	boolean hasPermittedTypes = this.permittedTypes != null && this.permittedTypes.length > 0;
 	if (hasPermittedTypes) {
 		if (!this.isSealed())
@@ -1170,11 +1162,13 @@ private void checkPermitsInType() {
 			return;
 		}
 	} else if (this.isNonSealed()) {
-		if (!foundSealedSuperTypeOrInterface) {
-			if (this.isClass() && !this.isRecord()) // record to give only illegal modifier error.
-				this.scope.problemReporter().sealedDisAllowedNonSealedModifierInClass(this, typeDecl);
-			else if (this.isInterface())
-				this.scope.problemReporter().sealedDisAllowedNonSealedModifierInInterface(this, typeDecl);
+		if (!this.isSealed()) { // lest we bark again.
+			if (!foundSealedSuperTypeOrInterface) {
+				if (this.isClass() && !this.isRecord()) // record to give only illegal modifier error.
+					this.scope.problemReporter().sealedDisAllowedNonSealedModifierInClass(this, typeDecl);
+				else if (this.isInterface())
+					this.scope.problemReporter().sealedDisAllowedNonSealedModifierInInterface(this, typeDecl);
+			}
 		}
 	}
 	if (foundSealedSuperTypeOrInterface) {
diff --git a/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/problem/ProblemReporter.java b/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/problem/ProblemReporter.java
index 3bb721eb34f..4f2b75af875 100644
--- a/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/problem/ProblemReporter.java
+++ b/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/problem/ProblemReporter.java
@@ -12397,15 +12397,6 @@ public void sealedSealedTypeMissingPermits(SourceTypeBinding type, ASTNode node)
 			node.sourceEnd);
 }
 
-public void sealedInterfaceIsSealedAndNonSealed(SourceTypeBinding type, ASTNode node) {
-	String name = new String(type.sourceName());
-	this.handle(IProblem.SealedInterfaceIsSealedAndNonSealed,
-			new String[] { name },
-			new String[] { name },
-			node.sourceStart,
-			node.sourceEnd);
-}
-
 public void sealedDisAllowedNonSealedModifierInInterface(SourceTypeBinding type, TypeDeclaration typeDecl) {
 	String name = new String(type.sourceName());
 	this.handle(
diff --git a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SealedTypesTests.java b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SealedTypesTests.java
index 7089df6ed0f..470cc748475 100644
--- a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SealedTypesTests.java
+++ b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SealedTypesTests.java
@@ -1071,11 +1071,6 @@ public void testBug563806_032() {
 			"	public sealed non-sealed interface X {\n" +
 			"	                                   ^\n" +
 			"Sealed class or interface lacks the permits clause and no class or interface from the same compilation unit declares X as its direct superclass or superinterface\n" +
-			"----------\n" +
-			"3. ERROR in p1\\X.java (at line 2)\n" +
-			"	public sealed non-sealed interface X {\n" +
-			"	                                   ^\n" +
-			"An interface X is declared both sealed and non-sealed\n" +
 			"----------\n");
 	}
 	public void testBug563806_033() {
@@ -6400,4 +6395,23 @@ final non-sealed class Y extends X  {}
 			    "The type Y may have only one modifier out of sealed, non-sealed, and final\n" +
 			    "----------\n");
 	}
+
+	// https://github.com/eclipse-jdt/eclipse.jdt.core/issues/3100
+	// [Sealed types] Duplicate diagnostics for illegal modifier combination
+	public void testIssue3100() {
+		runNegativeTest(
+				new String[] {
+						"X.java",
+						"""
+						public sealed non-sealed interface X {}
+						final class Y implements X  {}
+						"""
+				},
+				"----------\n" +
+				"1. ERROR in X.java (at line 1)\n" +
+				"	public sealed non-sealed interface X {}\n" +
+				"	                                   ^\n" +
+				"The type X may have only one modifier out of sealed, non-sealed, and final\n" +
+				"----------\n");
+	}
 }