Hello Waydown,
Thank you for your detailed description about problems.
Unfortunately I’ve not reproduced on beta version problem with video which skips backwards every few seconds and there is sound on all output files.
Please let us know where you playback your file. If you use player, please specify its version.
So it will be very helpful for us if you upload the original file to reproduce this problem.
As for MKV files with DTS audio, I have audio on such files. The audio wave is built maybe slow after the opening, but it builds and there is sound on the playback.
Please try to install
K-lite codec pack, possibly this will help.
Thanks.