diff --git a/libs/natls/build.gradle b/libs/natls/build.gradle
index 97877c3c8..cd47e18ae 100644
--- a/libs/natls/build.gradle
+++ b/libs/natls/build.gradle
@@ -10,6 +10,7 @@ dependencies {
     implementation project(':natlint')
 
     testImplementation project(':testhelpers')
+    testImplementation libraries.slf4j_nop
 }
 
 shadowJar {
@@ -18,6 +19,10 @@ shadowJar {
     archiveVersion.set('')
 }
 
+configurations.testImplementation {
+    exclude group: 'org.slf4j', module: libraries.slf4j_utillogging.split(':')[1]
+}
+
 jar {
     manifest {
         attributes(
diff --git a/libs/natls/src/main/java/org/amshove/natls/project/LanguageServerFile.java b/libs/natls/src/main/java/org/amshove/natls/project/LanguageServerFile.java
index fa0bab27d..b6d41603e 100644
--- a/libs/natls/src/main/java/org/amshove/natls/project/LanguageServerFile.java
+++ b/libs/natls/src/main/java/org/amshove/natls/project/LanguageServerFile.java
@@ -168,11 +168,15 @@ public void parse()
 
 	private boolean hasToReparseCallers(String newSource)
 	{
+		var tooManyCallers = incomingReferences.size() > 20;
+		if (!tooManyCallers && module.file().getFiletype() == NaturalFileType.COPYCODE)
+		{
+			return true;
+		}
+
 		var newDefineDataHash = hashDefineData(newSource);
 		var defineDataChanged = !Arrays.equals(newDefineDataHash, defineDataHash);
 		defineDataHash = newDefineDataHash;
-		var tooManyCallers = incomingReferences.size() > 20;
-		// TODO: Add trace log?
 
 		return !tooManyCallers && defineDataChanged;
 	}
diff --git a/libs/natls/src/test/java/org/amshove/natls/CallerReparseTest.java b/libs/natls/src/test/java/org/amshove/natls/CallerReparseTest.java
new file mode 100644
index 000000000..0bd18abed
--- /dev/null
+++ b/libs/natls/src/test/java/org/amshove/natls/CallerReparseTest.java
@@ -0,0 +1,95 @@
+package org.amshove.natls;
+
+import org.amshove.natls.testlifecycle.LanguageServerTest;
+import org.amshove.natls.testlifecycle.LspProjectName;
+import org.amshove.natls.testlifecycle.LspTestContext;
+import org.amshove.natparse.lexing.LexerError;
+import org.amshove.natparse.parsing.ParserError;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.AssertionsForInterfaceTypes.assertThat;
+
+class CallerReparseTest extends LanguageServerTest
+{
+	private static LspTestContext testContext;
+
+	@Override
+	protected LspTestContext getContext()
+	{
+		return testContext;
+	}
+
+	@Test
+	void savingACopyCodeShouldTriggerReparseOnCaller(@LspProjectName("emptyproject") LspTestContext context)
+	{
+		testContext = context;
+
+		createOrSaveFile("LIBONE", "MYCC.NSC", """
+			WRITE ''
+		""");
+
+		var subprog = createOrSaveFile("LIBONE", "MYSUB.NSN", """
+			DEFINE DATA LOCAL
+			END-DEFINE
+			INCLUDE MYCC
+			END
+		""");
+
+		var subprogramFile = findLanguageServerFile(subprog);
+
+		// Diagnostic from copy code is propagated to the subprogram
+		assertThat(subprogramFile.allDiagnostics())
+			.as("Expected diagnostic not found")
+			.anyMatch(d -> d.getCode().getLeft().equals(LexerError.INVALID_STRING_LENGTH.id()));
+
+		// Fix the diagnostic in the copy code
+		createOrSaveFile("LIBONE", "MYCC.NSC", """
+			WRITE 'Hi'
+		""");
+
+		// Diagnostic from copy code should not be present on subprogram anymore, because it was reparsed
+		assertThat(subprogramFile.allDiagnostics())
+			.as("Diagnostic shouldn't be present anymore")
+			.noneMatch(d -> d.getCode().getLeft().equals(LexerError.INVALID_STRING_LENGTH.id()));
+	}
+
+	@Test
+	void changingDefineDataShouldTriggerReparsing(@LspProjectName("emptyproject") LspTestContext context)
+	{
+		testContext = context;
+
+		createOrSaveFile("LIBONE", "MYLDA.NSL", """
+			DEFINE DATA
+			LOCAL
+			END-DEFINE
+		""");
+
+		var subprog = createOrSaveFile("LIBONE", "MYSUB.NSN", """
+			DEFINE DATA
+			LOCAL USING MYLDA
+			END-DEFINE
+			WRITE #HI
+			END
+		""");
+
+		var subprogramFile = findLanguageServerFile(subprog);
+
+		// Diagnostic from copy code is propagated to the subprogram
+		assertThat(subprogramFile.allDiagnostics())
+			.as("Expected diagnostic not found")
+			.anyMatch(d -> d.getCode().getLeft().equals(ParserError.UNRESOLVED_REFERENCE.id()));
+
+		// Adding the variable to the LDA to fix the diagnostic
+		createOrSaveFile("LIBONE", "MYLDA.NSL", """
+			DEFINE DATA
+			LOCAL
+			1 #HI (A10)
+			END-DEFINE
+		""");
+
+		// Diagnostic from copy code should not be present on subprogram anymore, because it was reparsed
+		assertThat(subprogramFile.allDiagnostics())
+			.as("Diagnostic shouldn't be present anymore")
+			.noneMatch(d -> d.getCode().getLeft().equals(ParserError.UNRESOLVED_REFERENCE.id()));
+	}
+}