I also have this issue on a pretty high end system... 9950X3D/5090 custom build. The weird thing is, if I'm in a tank or truck it just totally goes away! The second my boots hit the ground it's back. Really odd...
I only tested this briefly but I think you're right. I wonder if the issue lies with the camera positioning/rig for the first-person character model, as the third-person camera obviously will behave different to the first-person camera. Nice find though.
The issue doesn’t lie with the first person camera placement as that wouldn’t explain why using a controller it feels normal. Please read the entire post before attempting to come up with some reasoning for the issue.
