Audio / Video Sync Bug in 17?

I just finished a 25 minute video in the released version of Resolve 17.

After a rather computationally intensive first 14 seconds comes a simple three minute and 20 second segment of "talking head."

The problem is that, while playing the video back in edit mode in Resolve, the audio and video are properly synced. In the rendered video, the audio and video begin in sync, but by the end the audio very noticeably lags the video by a fraction of a second!

This is not good.

Any suggestions?

Which kind of sources?

Never mind. Turns out it was some sort of problem with the video player. I played the same video again, and there was no lag this time.

Sheesh! I'd never seen that before.