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 04ee92ff8b..f300fc045d 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
@@ -18,8 +18,10 @@ package org.springframework.boot.context.properties.source;
 
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Set;
 import java.util.stream.Stream;
 
 import org.springframework.core.env.EnumerablePropertySource;
@@ -129,7 +131,7 @@ class SpringIterableConfigurationPropertySource extends SpringConfigurationPrope
 	}
 
 	private Cache getCache() {
-		Object cacheKey = getCacheKey();
+		CacheKey cacheKey = CacheKey.get(getPropertySource());
 		if (cacheKey == null) {
 			return null;
 		}
@@ -137,17 +139,10 @@ class SpringIterableConfigurationPropertySource extends SpringConfigurationPrope
 			return this.cache;
 		}
 		this.cache = new Cache();
-		this.cacheKey = cacheKey;
+		this.cacheKey = cacheKey.copy();
 		return this.cache;
 	}
 
-	private Object getCacheKey() {
-		if (getPropertySource() instanceof MapPropertySource) {
-			return ((MapPropertySource) getPropertySource()).getSource().keySet();
-		}
-		return getPropertySource().getPropertyNames();
-	}
-
 	@Override
 	protected EnumerablePropertySource<?> getPropertySource() {
 		return (EnumerablePropertySource<?>) super.getPropertySource();
@@ -177,4 +172,48 @@ class SpringIterableConfigurationPropertySource extends SpringConfigurationPrope
 
 	}
 
+	private static final class CacheKey {
+
+		private Object key;
+
+		private CacheKey(Object key) {
+			this.key = key;
+		}
+
+		public CacheKey copy() {
+			return new CacheKey(copyKey(this.key));
+		}
+
+		private Object copyKey(Object key) {
+			if (key instanceof Set) {
+				return new HashSet<Object>((Set<?>) key);
+			}
+			return ((String[]) key).clone();
+		}
+
+		@Override
+		public int hashCode() {
+			return this.key.hashCode();
+		}
+
+		@Override
+		public boolean equals(Object obj) {
+			if (this == obj) {
+				return true;
+			}
+			if (obj == null || getClass() != obj.getClass()) {
+				return false;
+			}
+			return ObjectUtils.nullSafeEquals(this.key, ((CacheKey) obj).key);
+		}
+
+		public static CacheKey get(EnumerablePropertySource<?> source) {
+			if (source instanceof MapPropertySource) {
+				return new CacheKey(((MapPropertySource) source).getSource().keySet());
+			}
+			return new CacheKey(source.getPropertyNames());
+		}
+
+	}
+
 }
diff --git a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/logging/LoggingApplicationListenerTests.java b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/logging/LoggingApplicationListenerTests.java
index f05cb1f5ec..276fd8ac68 100644
--- a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/logging/LoggingApplicationListenerTests.java
+++ b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/logging/LoggingApplicationListenerTests.java
@@ -76,6 +76,7 @@ import static org.hamcrest.Matchers.not;
  * @author Andy Wilkinson
  * @author Stephane Nicoll
  * @author Ben Hale
+ * @author Fahim Farook
  */
 @RunWith(ModifiedClassPathRunner.class)
 @ClassPathExclusions("log4j*.jar")
@@ -500,12 +501,23 @@ public class LoggingApplicationListenerTests {
 	@Test
 	public void environmentPropertiesIgnoreUnresolvablePlaceholders() {
 		// gh-7719
+		TestPropertySourceUtils.addInlinedPropertiesToEnvironment(this.context,
+				"logging.pattern.console=console ${doesnotexist}");
+		this.initializer.initialize(this.context.getEnvironment(),
+				this.context.getClassLoader());
+		assertThat(System.getProperty(LoggingSystemProperties.CONSOLE_LOG_PATTERN))
+				.isEqualTo("console ${doesnotexist}");
+	}
+
+	@Test
+	public void environmentPropertiesResolvePlaceholders() {
 		TestPropertySourceUtils.addInlinedPropertiesToEnvironment(this.context,
 				"logging.pattern.console=console ${pid}");
 		this.initializer.initialize(this.context.getEnvironment(),
 				this.context.getClassLoader());
 		assertThat(System.getProperty(LoggingSystemProperties.CONSOLE_LOG_PATTERN))
-				.isEqualTo("console ${pid}");
+				.isEqualTo(this.context.getEnvironment()
+						.getProperty("logging.pattern.console"));
 	}
 
 	@Test
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 fd9a9d59b0..f75fe647f4 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
@@ -37,6 +37,7 @@ import static org.mockito.Mockito.mock;
  *
  * @author Phillip Webb
  * @author Madhura Bhave
+ * @author Fahim Farook
  */
 public class SpringIterableConfigurationPropertySourceTests {
 
@@ -157,6 +158,20 @@ public class SpringIterableConfigurationPropertySourceTests {
 				.isEqualTo(ConfigurationPropertyState.ABSENT);
 	}
 
+	@Test
+	public void propertySourceKeyDataChangeInvalidatesCache() {
+		// gh-13344
+		Map<String, Object> map = new LinkedHashMap<>();
+		map.put("key1", "value1");
+		map.put("key2", "value2");
+		EnumerablePropertySource<?> source = new MapPropertySource("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}.
 	 */