Audio sync lost in Edit after Fairlight edits

Dear All,

All seemed to be going quite well with a first project in DR, until I needed to remove some background noise from a clip in the timeline. Removal of unwanted noise with Fairlight went quite well, but after returning to the Edit page and doing some more edits, adding a few clips, shortening them, syncing them with the background music etc, I noticed that the audio goes out of sync.

In fact, when I return to the Fairlight Page, the audio goes berserk: it seems to loop and I hear different fragments of the various clips (it tries to play the timeline rather than the clip selected) and random noise and crackles. The video is still aligned with the timeline though.

Quit and restart of DR doesn't help. After reading through the forum a bit, I checked the clips out in the Colour Page, where all seems normal!

Clips are from an action cam @ 30fps and as far as I'm aware, so is the timeline.

EDIT: set up a new project with the same clips and even though I create optimised media for every clip in the timeline, the video starts to lag behind after only a few seconds. When I backup a bunch of frames and play again, audio and video are in sync, only for the video to start lagging behind soon ...

The diagnostics logs are here:
www [dot] tukcedo [dot] nl / extra / log_archive_20180722-164333.tgz

I observed same behavior using 15 beta 5 and 6, before I switched to 15 beta 4 that is stable as audio sync for me. Audio sync is essential for me, I never use camera audio.