[Kiko Matsing]

I have also experienced this using MacPro and iMac, different timeline compression setting and different video footage codec. I noticed that even i change already my edit, then render it, seems FCP is still reading the old rendered audio and video files on the scratch disk. By deleting them and rendering all again, it alway solve my problem with the syncing. But i have to make sure i deleted everything including my misplaced audio and video renders on other scratch disk. (sometimes i forget changing my scratch disk with other projects) You can try if it works with you.

[Kiko Matsing]

Hi, is the video compression of the timeline settings the same with the footages’ codec on your edit?

Try deleting all inside the audio renders and video rendered folder. Then render the timeline again. That will create a new set of rendered files that is going to be read when you playback.