While the Gallium performance overlay clearly shows a spike in the game's GPU
render time, I'm fairly certain it doesn't exist in the actual display output.
It's not limited to the character inventory, but instead happens anywhere, even
in the main menu. But I neither can see the cursor skipping, nor the camera in
game, despite of the graph's spike.
I also noticed that there is no such spike when the framerate is below the
refreshrate.

I also tested if there's something similar to observe in Hitman 2: I reduced
visual fidelity to achieve constant 75fps/Hz with vsync, and it always seems to
be 100% free of stutter, also when resuming to move the mouse after suspending
it for a few seconds.