I don't think that's it. If you try to connect a controller and pan the camera, the motion will be very smooth. From this we can conclude that the problem is most likely in the way the game processes the signal from the mouse, not the physics refresh rate or anything like that.
It definitely still happens on controller... I have tested with a controller and the same effect occurs. You have to move the character by strafing left or right and you will start to see it, then move by strafing left or right while panning the camera in the other direction. If you only pan the camera with right stick or mouse but your character is not moving, then it appears smooth.
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EDIT:
I feel like the game is gaslighting me...
Went to test it again and capture footage and now controller is perfect...
What I can definitively say from testing two scenarios with mixed inputs:
Strafing with controller left stick while using mouse to aim = bad, stutter.
Strafing with keyboard while using controller right stick to aim = good, smooth.
So I guess for now that's going to be my final input on this issue (no pun intended). Mouse input is still fundamentally broken and I am out of ideas.
Can you by chance record some slow-motion footage with your phone to show that? I don't own a controller so cant' do it myself. This is the first instance I've seen of someone saying controller is affected as well.
edited that reply, went to record it but couldn't replicate it again... if I manage to replicate it I'll upload slowmo footage.
