Yeah it is - a lot of ATX boards have a 1x slot above the GPU, while mATX boards and ITX boards have the GPU slot at the very top
Combine that with the new trend of really large GPU backplates, and you dont get much room
This is an ATX board which has 7 slots - where's #7 gone? Oh right, above the GPU.
To the right, the mATX variant - and that CPU-GPU gap is significantly smaller
To prevent the scale being an issue, heres an MS paint where i copied each boards AM4 stock bracket and rotated 90 degrees
If your CPU heatsink or GPU backplate have a live electrical current going through them, your PC is already dead.
If your GPU doesnt have a backplate, it wont contact because it'll be thinner.