diff --git a/src/libANGLE/renderer/vulkan/ContextVk.cpp b/src/libANGLE/renderer/vulkan/ContextVk.cpp
index 5adcdf29eb..7cd71ca526 100644
--- a/src/libANGLE/renderer/vulkan/ContextVk.cpp
+++ b/src/libANGLE/renderer/vulkan/ContextVk.cpp
@@ -1655,34 +1655,47 @@ angle::Result ContextVk::setupIndexedDraw(const gl::Context *context,
             vertexArrayVk->updateCurrentElementArrayBuffer();
         }
 
-        if (shouldConvertUint8VkIndexType(indexType) && mGraphicsDirtyBits[DIRTY_BIT_INDEX_BUFFER])
+        if (shouldConvertUint8VkIndexType(indexType))
         {
-            ANGLE_VK_PERF_WARNING(this, GL_DEBUG_SEVERITY_LOW,
-                                  "Potential inefficiency emulating uint8 vertex attributes due to "
-                                  "lack of hardware support");
+            if (mGraphicsDirtyBits[DIRTY_BIT_INDEX_BUFFER])
+            {
+                ANGLE_VK_PERF_WARNING(
+                    this, GL_DEBUG_SEVERITY_LOW,
+                    "Potential inefficiency emulating uint8 vertex attributes due to "
+                    "lack of hardware support");
 
-            BufferVk *bufferVk             = vk::GetImpl(elementArrayBuffer);
-            vk::BufferHelper &bufferHelper = bufferVk->getBuffer();
+                BufferVk *bufferVk             = vk::GetImpl(elementArrayBuffer);
+                vk::BufferHelper &bufferHelper = bufferVk->getBuffer();
 
-            if (bufferHelper.isHostVisible() &&
-                mRenderer->hasResourceUseFinished(bufferHelper.getResourceUse()))
-            {
-                uint8_t *src = nullptr;
-                ANGLE_TRY(bufferVk->mapForReadAccessOnly(this, reinterpret_cast<void **>(&src)));
-                // Note: bufferOffset is not added here because mapImpl already adds it.
-                src += reinterpret_cast<uintptr_t>(indices);
-                const size_t byteCount = static_cast<size_t>(elementArrayBuffer->getSize()) -
-                                         reinterpret_cast<uintptr_t>(indices);
-                BufferBindingDirty bindingDirty;
-                ANGLE_TRY(vertexArrayVk->convertIndexBufferCPU(this, indexType, byteCount, src,
-                                                               &bindingDirty));
-                ANGLE_TRY(bufferVk->unmapReadAccessOnly(this));
-            }
-            else
-            {
-                ANGLE_TRY(vertexArrayVk->convertIndexBufferGPU(this, bufferVk, indices));
+                if (bufferHelper.isHostVisible() &&
+                    mRenderer->hasResourceUseFinished(bufferHelper.getResourceUse()))
+                {
+                    uint8_t *src = nullptr;
+                    ANGLE_TRY(
+                        bufferVk->mapForReadAccessOnly(this, reinterpret_cast<void **>(&src)));
+                    // Note: bufferOffset is not added here because mapImpl already adds it.
+                    src += reinterpret_cast<uintptr_t>(indices);
+                    const size_t byteCount = static_cast<size_t>(elementArrayBuffer->getSize()) -
+                                             reinterpret_cast<uintptr_t>(indices);
+                    BufferBindingDirty bindingDirty;
+                    ANGLE_TRY(vertexArrayVk->convertIndexBufferCPU(this, indexType, byteCount, src,
+                                                                   &bindingDirty));
+                    ANGLE_TRY(bufferVk->unmapReadAccessOnly(this));
+                }
+                else
+                {
+                    ANGLE_TRY(vertexArrayVk->convertIndexBufferGPU(this, bufferVk, indices));
+                }
             }
 
+            // The converted (uint8->uint16) index buffer always holds the requested
+            // index range starting at offset 0, regardless of whether the conversion
+            // was re-run on this draw or reused from a previous draw with the same
+            // |indices|. mCurrentIndexBufferOffset was unconditionally set to the GL
+            // |indices| offset above; if we leave it and DIRTY_BIT_INDEX_BUFFER is
+            // later injected by flushDirtyGraphicsRenderPass(), handleDirtyGraphicsIndexBuffer
+            // would bind the small converted buffer at the (large) GL offset, causing a
+            // VkDeviceSize underflow / OOB vkCmdBindIndexBuffer offset.
             mCurrentIndexBufferOffset = 0;
         }
     }