Spec states that memory must be host mapped for flush.
https://registry.khronos.org/vulkan/specs/1.3/html/chap11.html#VUID-VkMappedMemoryRange-memory-00684

But Qt first unmaps and then flushes vma memory in different parts of code:

https://github.com/qt/qtbase/blob/dev/src/gui/rhi/qrhivulkan.cpp#L3240-L3241

vmaUnmapMemory(toVmaAllocator(allocator), a);
vmaFlushAllocation(toVmaAllocator(allocator), a, 0, stagingSize);

This causes a TON of validation errors which makes it impossible to extract useful information from validation layer.