diff --git a/headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/yaml/reconcile/ApplicationYamlASTReconciler.java b/headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/yaml/reconcile/ApplicationYamlASTReconciler.java
index 585c76837..e33b974d9 100644
--- a/headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/yaml/reconcile/ApplicationYamlASTReconciler.java
+++ b/headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/yaml/reconcile/ApplicationYamlASTReconciler.java
@@ -235,6 +235,9 @@ public class ApplicationYamlASTReconciler implements YamlASTReconciler {
 		if (typeUtil.isAtomic(type)) {
 			expectTypeFoundMapping(type, mapping);
 		} else if (typeUtil.isMap(type) || typeUtil.isSequencable(type)) {
+			if (typeUtil.isMap(type)) {
+				checkForEscapableKeys(mapping);
+			}
 			Type keyType = typeUtil.getKeyType(type);
 			Type valueType = TypeUtil.getDomainType(type);
 			if (keyType!=null) {
@@ -287,6 +290,36 @@ public class ApplicationYamlASTReconciler implements YamlASTReconciler {
 		}
 	}
 
+	private void checkForEscapableKeys(MappingNode mapping) {
+		if (mapping!=null) {
+			for (NodeTuple tup : mapping.getValue()) {
+				Node keyNode = tup.getKeyNode();
+				String key = NodeUtil.asScalar(keyNode);
+				if (needsEscaping(key)) {
+					problems.accept(problem(ApplicationYamlProblemType.YAML_SHOULD_ESCAPE, keyNode, 
+							"This key is used in a map and contains special characters. It is recommended to escape it by surrounding it with '[]'"));
+				}
+			}
+		}
+	}
+
+	private boolean needsEscaping(String key) {
+		if (key!=null) {
+			if (key.startsWith("[")) {
+				return false; // looks like its already escaped. So doesn't need more escaping.
+			}
+			for (int i = 0; i < key.length(); i++) {
+				char c = key.charAt(i);
+				if (c=='-'||Character.isAlphabetic(c)||Character.isDigit(c)) {
+					//fine!
+				} else {
+					return true;
+				}
+			}
+		}
+		return false;
+	}
+
 	private void reconcile(YamlFileAST root, SequenceNode seq, Type type) {
 		if (typeUtil.isAtomic(type)) {
 			expectTypeFoundSequence(type, seq);
diff --git a/headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/yaml/reconcile/ApplicationYamlProblemType.java b/headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/yaml/reconcile/ApplicationYamlProblemType.java
index 0e8d3619c..45f903ae0 100644
--- a/headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/yaml/reconcile/ApplicationYamlProblemType.java
+++ b/headless-services/spring-boot-language-server/src/main/java/org/springframework/ide/vscode/boot/yaml/reconcile/ApplicationYamlProblemType.java
@@ -32,7 +32,8 @@ public enum ApplicationYamlProblemType implements ProblemType {
 	YAML_INVALID_BEAN_PROPERTY("Accessing a named property in a type that doesn't provide a property accessor with that name"),
 	YAML_DEPRECATED_ERROR(ERROR, "Property is marked as Deprecated(Error)"),
 	YAML_DEPRECATED_WARNING(WARNING, "Property is marked as Deprecated(Warning)"),
-	YAML_DUPLICATE_KEY("A mapping node contains multiple entries for the same key");
+	YAML_DUPLICATE_KEY("A mapping node contains multiple entries for the same key"),
+	YAML_SHOULD_ESCAPE(WARNING, "This key contains special characters and should probably be escaped by surrounding it with '[]'");
 
 	private final ProblemSeverity defaultSeverity;
 	private String description;
diff --git a/headless-services/spring-boot-language-server/src/test/java/org/springframework/ide/vscode/boot/test/ApplicationYamlEditorTest.java b/headless-services/spring-boot-language-server/src/test/java/org/springframework/ide/vscode/boot/test/ApplicationYamlEditorTest.java
index c40512b25..2b8168119 100644
--- a/headless-services/spring-boot-language-server/src/test/java/org/springframework/ide/vscode/boot/test/ApplicationYamlEditorTest.java
+++ b/headless-services/spring-boot-language-server/src/test/java/org/springframework/ide/vscode/boot/test/ApplicationYamlEditorTest.java
@@ -130,6 +130,26 @@ public class ApplicationYamlEditorTest extends AbstractPropsEditorTest {
 		);
 	}
 
+	@Test public void test_GH_534_warning() throws Exception {
+		//See: https://www.pivotaltracker.com/n/projects/1346850/stories/174872660
+		IJavaProject p = createPredefinedMavenProject("map-of-pojo");
+		useProject(p);
+		
+		//detect values in map keys that are recommended to be escpaped.
+		Editor editor = newEditor(
+				"my:\n" + 
+				"  map:\n" + 
+				"    foo.bar:\n" + 
+				"      name: jeff\n" +
+				"    '[rab.dab]':\n" + //no warn for this, already escaped! 
+				"      name: jeff\n" +
+				"    yaza:\n" +  //nothing special, so no warning either.
+				"      name: good"
+		);
+		Diagnostic problem = editor.assertProblems("foo.bar|escape it by surrounding it with '[]'").get(0);
+		assertEquals(DiagnosticSeverity.Warning, problem.getSeverity());
+	}
+
 	@Test public void handleAsKey() throws Exception {
 		//See: https://www.pivotaltracker.com/story/show/174954118
 		useProject(createPredefinedMavenProject("justauth-example"));
diff --git a/headless-services/spring-boot-language-server/src/test/resources/test-projects/map-of-pojo/src/main/resources/application.yml b/headless-services/spring-boot-language-server/src/test/resources/test-projects/map-of-pojo/src/main/resources/application.yml
new file mode 100644
index 000000000..83afce13b
--- /dev/null
+++ b/headless-services/spring-boot-language-server/src/test/resources/test-projects/map-of-pojo/src/main/resources/application.yml
@@ -0,0 +1,4 @@
+my:
+  map:
+    foo.bar:
+      name: jeff
\ No newline at end of file