When I press shift (sneak) in creative mode, the position of my arm in 1st person view changes. This seems to be both in Creative mode as well as in Survival mode.

When I press shift, I'd expect the arm stays at it's normal position, instead of moving a bit.

The position of my arm moved a slight bit to the bottom right corner of the screen when I pressed Shift.

Step 1: Open any world.
Step 2: Press to sneak.
Step 3: See the bug.