If the problem begins right after the patch on 7/17/2020, then you may switch back to the stable build on 6/27. Just open the game properties, and click "stable". It will be automatically downloaded for you.
If you have such issue, please leave a comment and let me know about:
- your hardware spec (including your keyboard, mouse, and controller)
- OS and GPU driver version
- if you use a controller in this game
- did you encounter any stutter in the "map editing" mode.
- anything else that may be relevant to this issue