diff --git a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/source/SpringIterableConfigurationPropertySource.java b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/source/SpringIterableConfigurationPropertySource.java
index 241ce2180b05..870c6f1b7abc 100644
--- a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/source/SpringIterableConfigurationPropertySource.java
+++ b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/source/SpringIterableConfigurationPropertySource.java
@@ -24,6 +24,7 @@
 import java.util.Set;
 import java.util.stream.Stream;
 
+import org.springframework.boot.env.OriginTrackedMapPropertySource;
 import org.springframework.core.env.EnumerablePropertySource;
 import org.springframework.core.env.MapPropertySource;
 import org.springframework.core.env.PropertySource;
@@ -44,7 +45,7 @@
 class SpringIterableConfigurationPropertySource extends SpringConfigurationPropertySource
 		implements IterableConfigurationPropertySource {
 
-	private volatile Object cacheKey;
+	private volatile CacheKey cacheKey;
 
 	private volatile Cache cache;
 
@@ -173,21 +174,37 @@ private static final class CacheKey {
 
 		private final Object key;
 
-		private CacheKey(Object key) {
+		private final int size;
+
+		private final boolean unmodifiableKey;
+
+		private CacheKey(Object key, boolean unmodifiableKey) {
 			this.key = key;
+			this.size = calculateSize(key);
+			this.unmodifiableKey = unmodifiableKey;
 		}
 
 		public CacheKey copy() {
-			return new CacheKey(copyKey(this.key));
+			return new CacheKey(copyKey(this.key), this.unmodifiableKey);
 		}
 
 		private Object copyKey(Object key) {
+			if (this.unmodifiableKey) {
+				return key;
+			}
 			if (key instanceof Set) {
 				return new HashSet<Object>((Set<?>) key);
 			}
 			return ((String[]) key).clone();
 		}
 
+		private int calculateSize(Object key) {
+			if (key instanceof Set) {
+				return ((Set<?>) key).size();
+			}
+			return ((String[]) key).length;
+		}
+
 		@Override
 		public boolean equals(Object obj) {
 			if (this == obj) {
@@ -196,7 +213,11 @@ public boolean equals(Object obj) {
 			if (obj == null || getClass() != obj.getClass()) {
 				return false;
 			}
-			return ObjectUtils.nullSafeEquals(this.key, ((CacheKey) obj).key);
+			CacheKey otherCacheKey = (CacheKey) obj;
+			if (this.size != otherCacheKey.size) {
+				return false;
+			}
+			return ObjectUtils.nullSafeEquals(this.key, otherCacheKey.key);
 		}
 
 		@Override
@@ -206,9 +227,10 @@ public int hashCode() {
 
 		public static CacheKey get(EnumerablePropertySource<?> source) {
 			if (source instanceof MapPropertySource) {
-				return new CacheKey(((MapPropertySource) source).getSource().keySet());
+				return new CacheKey(((MapPropertySource) source).getSource().keySet(),
+						source instanceof OriginTrackedMapPropertySource);
 			}
-			return new CacheKey(source.getPropertyNames());
+			return new CacheKey(source.getPropertyNames(), false);
 		}
 
 	}
diff --git a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/source/SpringIterableConfigurationPropertySourceTests.java b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/source/SpringIterableConfigurationPropertySourceTests.java
index 6e5b608fe173..7ad5ff9b4dc7 100644
--- a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/source/SpringIterableConfigurationPropertySourceTests.java
+++ b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/source/SpringIterableConfigurationPropertySourceTests.java
@@ -21,6 +21,7 @@
 
 import org.junit.Test;
 
+import org.springframework.boot.env.OriginTrackedMapPropertySource;
 import org.springframework.boot.origin.Origin;
 import org.springframework.boot.origin.OriginLookup;
 import org.springframework.core.env.EnumerablePropertySource;
@@ -156,7 +157,7 @@ public void containsDescendantOfShouldCheckSourceNames() {
 	}
 
 	@Test
-	public void propertySourceKeyDataChangeInvalidatesCache() {
+	public void simpleMapPropertySourceKeyDataChangeInvalidatesCache() {
 		// gh-13344
 		Map<String, Object> map = new LinkedHashMap<>();
 		map.put("key1", "value1");
@@ -169,6 +170,21 @@ public void propertySourceKeyDataChangeInvalidatesCache() {
 		assertThat(adapter.stream().count()).isEqualTo(3);
 	}
 
+	@Test
+	public void originTrackedMapPropertySourceKeyAdditionInvalidatesCache() {
+		// gh-13344
+		Map<String, Object> map = new LinkedHashMap<>();
+		map.put("key1", "value1");
+		map.put("key2", "value2");
+		EnumerablePropertySource<?> source = new OriginTrackedMapPropertySource("test",
+				map);
+		SpringIterableConfigurationPropertySource adapter = new SpringIterableConfigurationPropertySource(
+				source, DefaultPropertyMapper.INSTANCE);
+		assertThat(adapter.stream().count()).isEqualTo(2);
+		map.put("key3", "value3");
+		assertThat(adapter.stream().count()).isEqualTo(3);
+	}
+
 	/**
 	 * Test {@link PropertySource} that's also an {@link OriginLookup}.
 	 */