Hi,

What AutoCAD version your are using now?
If it is 2020 or 2021 version:
Do you use AutoCAD with Retina (or other Hi-Res) display?
Have you tried to run AutoCAD in Low resolution (right-click on AutoCAD.app -> Get Info -> Check-mark "Open in Low Resolution" and relaunch AutoCAD)
Do you think the OSNAP inaccuracy problem starts immediately after the launch of AutoCAD or does it need to work in the program for a while so that this problem begins to manifest itself?