diff --git a/Docs/Whats_New.md b/Docs/Whats_New.md
index add2a09e..0dd33d02 100644
--- a/Docs/Whats_New.md
+++ b/Docs/Whats_New.md
@@ -24,6 +24,7 @@ Released TBD
 - Support separate depth and stencil attachments during dynamic rendering.
 - Deprecate the obsolete and non-standard `VK_MVK_moltenvk` extension.
 - Fix memory leak when waiting on timeline semaphores.
+- Fix race condition when updating values in `VkPastPresentationTimingGOOGLE`.
 - Ensure shaders that use `PhysicalStorageBufferAddresses` encode the use of the associated `MTLBuffer`.
 - Disable pipeline cache compression prior to macOS 10.15 and iOS/tvOS 13.0.
 - Add `MVK_ENABLE_EXPLICIT_LOD_WORKAROUND` environment variable to selectively 
diff --git a/MoltenVK/MoltenVK/GPUObjects/MVKImage.h b/MoltenVK/MoltenVK/GPUObjects/MVKImage.h
index fadc2504..db83c323 100644
--- a/MoltenVK/MoltenVK/GPUObjects/MVKImage.h
+++ b/MoltenVK/MoltenVK/GPUObjects/MVKImage.h
@@ -449,7 +449,7 @@ public:
 #pragma mark Metal
 
 	/** Presents the contained drawable to the OS. */
-	void presentCAMetalDrawable(id<MTLCommandBuffer> mtlCmdBuff, MVKImagePresentInfo& presentInfo);
+	void presentCAMetalDrawable(id<MTLCommandBuffer> mtlCmdBuff, MVKImagePresentInfo presentInfo);
 
 
 #pragma mark Construction
@@ -463,7 +463,7 @@ protected:
 	friend MVKSwapchain;
 
 	id<CAMetalDrawable> getCAMetalDrawable() override;
-	void addPresentedHandler(id<CAMetalDrawable> mtlDrawable, MVKImagePresentInfo& presentInfo);
+	void addPresentedHandler(id<CAMetalDrawable> mtlDrawable, MVKImagePresentInfo presentInfo);
 	void releaseMetalDrawable();
 	MVKSwapchainImageAvailability getAvailability();
 	void makeAvailable(const MVKSwapchainSignaler& signaler);
diff --git a/MoltenVK/MoltenVK/GPUObjects/MVKImage.mm b/MoltenVK/MoltenVK/GPUObjects/MVKImage.mm
index a71d5eda..b8cfc68e 100644
--- a/MoltenVK/MoltenVK/GPUObjects/MVKImage.mm
+++ b/MoltenVK/MoltenVK/GPUObjects/MVKImage.mm
@@ -1294,8 +1294,9 @@ id<CAMetalDrawable> MVKPresentableSwapchainImage::getCAMetalDrawable() {
 }
 
 // Present the drawable and make myself available only once the command buffer has completed.
+// Pass MVKImagePresentInfo by value because it may not exist when the callback runs.
 void MVKPresentableSwapchainImage::presentCAMetalDrawable(id<MTLCommandBuffer> mtlCmdBuff,
-														  MVKImagePresentInfo& presentInfo) {
+														  MVKImagePresentInfo presentInfo) {
 	lock_guard<mutex> lock(_availabilityLock);
 
 	_swapchain->willPresentSurface(getMTLTexture(0), mtlCmdBuff);
@@ -1357,8 +1358,9 @@ void MVKPresentableSwapchainImage::presentCAMetalDrawable(id<MTLCommandBuffer> m
 	signalPresentationSemaphore(signaler, mtlCmdBuff);
 }
 
+// Pass MVKImagePresentInfo by value because it may not exist when the callback runs.
 void MVKPresentableSwapchainImage::addPresentedHandler(id<CAMetalDrawable> mtlDrawable,
-													   MVKImagePresentInfo& presentInfo) {
+													   MVKImagePresentInfo presentInfo) {
 #if !MVK_OS_SIMULATOR
 	if ([mtlDrawable respondsToSelector: @selector(addPresentedHandler:)]) {
 		retain();	// Ensure this image is not destroyed while awaiting presentation
diff --git a/MoltenVK/MoltenVK/GPUObjects/MVKSwapchain.h b/MoltenVK/MoltenVK/GPUObjects/MVKSwapchain.h
index 47a26d2a..95bcb137 100644
--- a/MoltenVK/MoltenVK/GPUObjects/MVKSwapchain.h
+++ b/MoltenVK/MoltenVK/GPUObjects/MVKSwapchain.h
@@ -121,7 +121,7 @@ protected:
     void willPresentSurface(id<MTLTexture> mtlTexture, id<MTLCommandBuffer> mtlCmdBuff);
     void renderWatermark(id<MTLTexture> mtlTexture, id<MTLCommandBuffer> mtlCmdBuff);
     void markFrameInterval();
-	void recordPresentTime(MVKImagePresentInfo& presentInfo, uint64_t actualPresentTime = 0);
+	void recordPresentTime(const MVKImagePresentInfo& presentInfo, uint64_t actualPresentTime = 0);
 
 	CAMetalLayer* _mtlLayer = nil;
     MVKWatermark* _licenseWatermark = nullptr;
diff --git a/MoltenVK/MoltenVK/GPUObjects/MVKSwapchain.mm b/MoltenVK/MoltenVK/GPUObjects/MVKSwapchain.mm
index 53aba660..2f4c1d18 100644
--- a/MoltenVK/MoltenVK/GPUObjects/MVKSwapchain.mm
+++ b/MoltenVK/MoltenVK/GPUObjects/MVKSwapchain.mm
@@ -557,7 +557,7 @@ VkResult MVKSwapchain::getPastPresentationTiming(uint32_t *pCount, VkPastPresent
 	return res;
 }
 
-void MVKSwapchain::recordPresentTime(MVKImagePresentInfo& presentInfo, uint64_t actualPresentTime) {
+void MVKSwapchain::recordPresentTime(const MVKImagePresentInfo& presentInfo, uint64_t actualPresentTime) {
 	std::lock_guard<std::mutex> lock(_presentHistoryLock);
 	if (_presentHistoryCount < kMaxPresentationHistory) {
 		_presentHistoryCount++;