diff --git a/MobileGL/MG_Backend/DirectVulkan/Renderer/GpuProgressMarkers.cpp b/MobileGL/MG_Backend/DirectVulkan/Renderer/GpuProgressMarkers.cpp
index 681724fc..e0522e38 100644
--- a/MobileGL/MG_Backend/DirectVulkan/Renderer/GpuProgressMarkers.cpp
+++ b/MobileGL/MG_Backend/DirectVulkan/Renderer/GpuProgressMarkers.cpp
@@ -96,7 +96,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         return true;
     }
 
-    GpuProgressMarkers::Bracket GpuProgressMarkers::Acquire() {
+    GpuProgressMarkers::Bracket GpuProgressMarkers::Acquire(Uint64 completedSubmitIndex) {
         Bracket bracket;
         if (m_device == VK_NULL_HANDLE) return bracket;
         const std::lock_guard<std::mutex> lock(m_mutex);
@@ -106,7 +106,8 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             if (slot.Claimed) continue;
             // Retire what finished since the watch last looked: frames come faster than its polls.
             if (slot.InFlight && vkGetEventStatus(m_device, slot.Finished) == VK_EVENT_SET) slot.InFlight = false;
-            if (!slot.InFlight && free == nullptr) free = &slot;
+            // Free once its submission is complete by fence, not by the event read (see the header).
+            if (!slot.InFlight && slot.SubmitIndex <= completedSubmitIndex && free == nullptr) free = &slot;
         }
         if (free == nullptr) {
             if (!AddSlot()) return bracket;
@@ -125,7 +126,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         return bracket;
     }
 
-    void GpuProgressMarkers::Submitted(const Bracket& bracket) {
+    void GpuProgressMarkers::Submitted(const Bracket& bracket, Uint64 submitIndex) {
         if (!bracket.Valid()) return;
         const std::lock_guard<std::mutex> lock(m_mutex);
         if (bracket.Slot >= m_slots.size()) return;
@@ -133,6 +134,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         slot.Claimed = false;
         slot.InFlight = true;
         slot.Dirty = true;
+        slot.SubmitIndex = submitIndex;
         slot.Id = m_nextId++;
     }
 
diff --git a/MobileGL/MG_Backend/DirectVulkan/Renderer/GpuProgressMarkers.h b/MobileGL/MG_Backend/DirectVulkan/Renderer/GpuProgressMarkers.h
index 2dcbf268..f1649939 100644
--- a/MobileGL/MG_Backend/DirectVulkan/Renderer/GpuProgressMarkers.h
+++ b/MobileGL/MG_Backend/DirectVulkan/Renderer/GpuProgressMarkers.h
@@ -50,9 +50,18 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         // The two buffers to put first and last in one submission (an invalid bracket when off or
         // when every slot is in flight: the submission then goes unwatched).
-        Bracket Acquire();
-        // The submission carrying `bracket` was accepted by vkQueueSubmit / was not submitted.
-        void Submitted(const Bracket& bracket);
+        //
+        // A slot is reused only once the submission it last bracketed is COMPLETE by its fence
+        // (`completedSubmitIndex`, the renderer's contiguous completed-submit floor), not merely once
+        // the host has read its `finished` event as set. A host read of an event gives no device-side
+        // ordering: nothing orders the bracket's `started` set (TOP_OF_PIPE, first buffer) against
+        // its `finished` set, so a host vkResetEvent plus a re-set in a later submission could
+        // overlap a set the earlier submission has not executed yet. The synchronization validator
+        // reports that as SYNC-vkCmdSetEvent-missingbarrier-set. Event reads still drive the watch.
+        Bracket Acquire(Uint64 completedSubmitIndex);
+        // The submission carrying `bracket` (renderer submit index `submitIndex`) was accepted by
+        // vkQueueSubmit / was not submitted.
+        void Submitted(const Bracket& bracket, Uint64 submitIndex);
         void Abandon(const Bracket& bracket);
 
         // The watch named one of this device's submissions as hanging the GPU.
@@ -74,6 +83,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             Bool InFlight = false; // submitted and not yet seen finished
             Bool Claimed = false;  // handed out by Acquire, not yet submitted or abandoned
             Bool Dirty = false;    // its events were set by a past submission: reset before reuse
+            Uint64 SubmitIndex = 0; // the renderer submit index of the submission it last bracketed
         };
         static constexpr Uint32 kMaxSlots = 16;
 
diff --git a/MobileGL/MG_Backend/DirectVulkan/Renderer/VulkanRenderer.cpp b/MobileGL/MG_Backend/DirectVulkan/Renderer/VulkanRenderer.cpp
index de9e7b8b..650f68c4 100644
--- a/MobileGL/MG_Backend/DirectVulkan/Renderer/VulkanRenderer.cpp
+++ b/MobileGL/MG_Backend/DirectVulkan/Renderer/VulkanRenderer.cpp
@@ -6117,9 +6117,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         if (LatchIfGpuHung("flush-submit")) return false;
         SharedImageSubmitSync sharedImageSync;
         AttachSharedImageSync(submitInfo, sharedImageSync);
-        const GpuProgressMarkers::Bracket bracket = m_progressMarkers.Acquire();
+        const GpuProgressMarkers::Bracket bracket = m_progressMarkers.Acquire(m_completedSubmitCounter);
         const VkResult result = GpuProgressMarkers::SubmitBracketed(m_graphicsQueue, submitInfo, fence, bracket);
-        if (result == VK_SUCCESS) m_progressMarkers.Submitted(bracket);
+        if (result == VK_SUCCESS) m_progressMarkers.Submitted(bracket, m_submitCounter + 1); // RegisterSubmit below
         else m_progressMarkers.Abandon(bracket);
 #else
         const VkResult result = vkQueueSubmit(m_graphicsQueue, 1, &submitInfo, fence);
@@ -6586,10 +6586,10 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         if (LatchIfGpuHung("present-submit")) return;
         SharedImageSubmitSync sharedImageSync;
         AttachSharedImageSync(submitPacket.submitInfo, sharedImageSync);
-        const GpuProgressMarkers::Bracket bracket = m_progressMarkers.Acquire();
+        const GpuProgressMarkers::Bracket bracket = m_progressMarkers.Acquire(m_completedSubmitCounter);
         const VkResult presentSubmit = GpuProgressMarkers::SubmitBracketed(m_graphicsQueue, submitPacket.submitInfo,
                                                                            frame.imageInFlightFence, bracket);
-        if (presentSubmit == VK_SUCCESS) m_progressMarkers.Submitted(bracket);
+        if (presentSubmit == VK_SUCCESS) m_progressMarkers.Submitted(bracket, m_submitCounter + 1); // RegisterSubmit below
         else m_progressMarkers.Abandon(bracket);
 #else
         const VkResult presentSubmit = vkQueueSubmit(m_graphicsQueue, 1, &submitPacket.submitInfo, frame.imageInFlightFence);