We've got this report a few times, and we think it might be related to the way the web build is interacting with your browser and hardware. We have release a Windows build that a few people have mentioned cleared the issue up, so if you'd like, you can try that!
If you'd like to, if you could message me your browser/version, CPU/GPU, and whether or not you're using hardware acceleration, that may give us more information to test our builds with in the future! Thanks~