After successfully running (verified in xcode metal profiler) a simple compute shader, QRhiResourceUpdateBatch::readBackBuffer() fails to return the results. I've attached a simple program to reproduce the issue. The program creates 3 buffers. The first two buffers of 10 float are added and outputted to the 3 buffer. 

Example code can be found here: https://github.com/vpicaver/qt_rhi_compute_shader

The output on my machine is:

Metal QRhiDriverInfo(deviceName="AMD Radeon Pro 580" deviceId=0x0 vendorId=0x0 deviceType=Integrated)
compute supported: true
read non uniform buffer: true
Shader valid: true
endComputePass
endOffscreenFrame
i: 0 value: -1
i: 1 value: -1
i: 2 value: -1
i: 3 value: -1
i: 4 value: -1
i: 5 value: -1
i: 6 value: -1
i: 7 value: -1
i: 8 value: -1
i: 9 value: -1
finish
Finished with frame!
 

There shouldn't be -1 for the values of the output buffer.

This code works on an nvidia 1070 on windows 11 running with Directx12 and Vulkan.