Hello everyone,,
I've been using vMix for 3+ years, and generally love it.

For most of that time, due to my workflow, I've been recording DV to AVI files, but I want to finally transition to HD. As an interim step, I'm recording SD to ProRes, as I'm on Mac using FCP 7 as my final finishing tool, it doesn't like the MP4s from vMix. However, ProRes files work great, roadrunner email except for one problem.

Obviously, in order to use them, they need to be indexed. I have chosen to index after recording, to have fault tolerance. Had the power go out a few months ago (first time in 10 years!) and had a nightmare trying to rebuild those AVI files. However, whether I use the vMix indexing tool on PC, or index through FFMPEG on my Mac, the audio is generally about a half a second out of sync.

I can compensate for this in my post work, but it would be better if it didn't happen at all! Any guidance?

This is happening both for my SD recordings, and in tests I did in HD. Haven't yet tried saving indexed, but if I do that, I lose fault tolerance. I also don't want to record in chunks if I can avoid it, as that leads to other issues in my workflow.
Thanks for any help you can provide!

* my version of vMix is the full version released around the end of 2016. Running a custom PC with specs matching the sample specs on the vMix site from that time. AVI and MP4 recordings did not have this sync issue.