Operating system: Windows-10-10.0.17134 64 Bits
Graphics card: Radeon RX 580 Series ATI Technologies Inc. 4.5.13521 Core Profile Context 24.20.11021.1000
CPU: AMD FX-8350 8 core 4 GHz
RAM: 2x4 GB + 2x8 GB (24 GB)
Broken: version: 2.80 (sub 75), branch: master, commit date: 2019-07-29 14:47, hash: rBf6cb5f54494e
Short description of error
I've been struggling for hours to get video editing to work. The nodes are correct, the viewer (and the backdrop) displays the output perfectly fine. It's also connected to the composite. The problem is, the preview displays wrong, the keying and the alpha over is disregarded, and it won't render right. The rendered pic is still the preview you see on the attached screenshot.
I looked up several possible solutions to no avail. I sent the file to my friend and he had no problem, it should work fine, so it must be something to do with my rig. It might be a hardware related bug, but I'm not sure.
Exact steps for others to reproduce the error
None that I know of, it worked for my friend. That's why I'm writing a bug report instead of just asking on a forum how to do it. I had issues with my GPU previously regarding to Blender 2.79 - none of the textures would render, while they worked for my friend, and in the meanwhile, rendering with CPU worked for me. I suspect I got lucky again...