Vehicles aren't centered on rendering
The expectation is (0,0,0) corresponds with the center of the vehicle by default and a pixel Y offset won't be required. I currently have to offset by -16. to get the vehicle properly positioned.
Project file: busproject.zip
I believe there's already an additional offset that gets added when you enable vehicle rendering. Are you using the vehicle renderer?
yes
I pressed F12 and it's clear the camera isn't pointed at 0,0, so the issue is likely not the post processing:

Nah this is a special process, centering the final render on the center would waste 1/3rd of the view in most cases. This is adjusted for later on in the final offsets (if that still works)
Rendering with the camera offset zeroed out yields the same offsets, so it's clearly taking that into account.
I have no idea what the root cause is but I can counteract it by setting the frame offset to (0, -16) in the operators.
To my knowledge vehicles still have a different base offset, just check it with a single pixel at 0,0,0 without using the add-on
Where is the base offset defined?