With OBS recordings (not streaming) on Linux I occasionally get situations where short but heavy disk or network I/O will cause my webcam's video to get out of sync with my microphone (separate mic from the webcam). This makes it look like my lips are way out of sync with the video. It's something I haven't been able to track down as there's no errors or side effects posted in journald logs.

This is using vanilla Arch with niri. It happens pretty often and I fix it by splitting the audio and video in my editing tool and then shifting the audio track over half a second or so.

I recorded over 1,000 videos on Windows with the same hardware and the above never happened once.