Something went wrong in After Effects. It's not only one project, I tried different, but the problem remains. It's well visible on the screenshot. Please help.
I see the display anomaly, but I also see that the Boy R comp is incredibly small. Just 152 X 199. Your comps should always be an even number of pixels high and wide, and the lines in the Illustration are not going to compress well.
I also see that display acceleration is turned off. Are Fast Previews to Final Quality or Adaptive Resolution?
I would also double-check the AE Preferences Display settings (Alt/Option + Ctrl/Cmnd + ; ) and I would check the Project settings (Shift + Alt/Option + Ctrl/Cmnd + k).
If all else fails, create a new empty AEP, import the problematic AEP file instead of opening it, and see what that does.