I've read it might be NVIDIA antialiasing that is interfeering, try with these steps:
1. Open the Nvidia Control Panel
2. Manage 3D settings
3. Program Settings > Add > Godot Engine Nvidia profile
4. Turn off all "Antialiasing - " settings
Let me know if it still doesn't work, if you can provide me some infos like OS, pc specs and stuff i can try to replicate the issue in some way It might also be caused by outdated drivers