Chord symbols entered into score not parsed in parts
1) default score
2) generate parts
3) enter a note in measure 1 (to eliminate mmrests from the equation)
4) enter chord symbol Eb
5) view part
Result: instead of a flat sign, you have just the letter "b", indicating we didn't parse the chord symbol in the part at all - it was just a straight text copy. This is probably what is preventing transposition from working as per #248891: Chord symbols transposed incorrectly between concert score & transposed parts, although the issue with Notes / Transpose is different since it also affected 2.x. It's also going to play havoc with everything else involving chord symbols.
Needless to say (?), extremely critical. I suspect much of the original code I wrote having to do with chord symbol parsing is badly out of date, I will take a look and see what I can figure out.