Sorry to hear about sound sync problem. I had a problem once when my recording was shut down unexpected, when battery went empty.
I use raw2cdng, and a new version of that couldn't solv the sync problem from MLV files, so I tried an old one 1.6.1 and that fixed it. Even tought I think the video and audio had different lengtes, it synced perfectly in Resolve.
Well, really sorry to hear, maybe it could be fixed with some effort.
For most people using this camera is just a cdng with synced audio the most important thing from a MLV/RAW converting app.
They are free and has to be i guess, you can do donation (which I did a small amount to Chmee) but its really bad that there are so many that shits it up

but some do it really properly like for example Chmee and others did.
Well its free this, but this can't happen anyway I think, It's so crucial for stuff like this to work.
The raw2cdng app that I was using is sort of 4 years old and it was perfect never had a problem with it, except from now on latest Windows Updates which rolled me back even to an older raw2cdng app.