diff --git a/packages/lib/models/Setting.test.ts b/packages/lib/models/Setting.test.ts
index b6ded4edad0..3566f36ff75 100644
--- a/packages/lib/models/Setting.test.ts
+++ b/packages/lib/models/Setting.test.ts
@@ -226,6 +226,14 @@ describe('models/Setting', function() {
 		expect(Setting.value('style.editor.contentMaxWidth')).toBe(600); // Changed
 	}));
 
+	it('should skip values that are already set', (async () => {
+		await Setting.reset();
+
+		Setting.setValue('sync.target', 9);
+		Setting.applyDefaultMigrations();
+		expect(Setting.value('sync.target')).toBe(9); // Not changed
+	}));
+
 	it('should allow skipping default migrations', (async () => {
 		await Setting.reset();
 
diff --git a/packages/lib/models/Setting.ts b/packages/lib/models/Setting.ts
index a079d42df85..23910e9be4b 100644
--- a/packages/lib/models/Setting.ts
+++ b/packages/lib/models/Setting.ts
@@ -1457,7 +1457,7 @@ class Setting extends BaseModel {
 	}
 
 	public static isSet(key: string) {
-		return key in this.cache_;
+		return this.cache_.find(d => d.key === key);
 	}
 
 	static keyDescription(key: string, appType: AppType = null) {