Hi, I have ripped Attack on Titan: Season 2 the Funanimation one and I usually create a backup then rip from said backup, i have created two backups so i can test to see if it was a faulty backup though there are no error codes when making the backup just when ripping to MKV which i get this error.
DEBUG: Code 0 at :WQfc~\>#=_|hz]uopm:121261911
DEBUG: Code 3199971767 at NA*r*2BG==&AH:213132537
The files appear to work that is depositied no idea what the issue is though.
I use a similar workflow to you and I occasionally get some DEBUG codes in the logs. I've never noticed them to be a problem so I don't worry about them.
MakeMKV is usually pretty clear when there's some kind of real error. DEBUG codes in the log are merely informational for the developer of MakeMKV.