I'm almost finished replaying BS1 and BS2 in preparation for taking on BS3 for the first time, and I've hit a bug that I didn't encounter on my first playthroughs. All my horseborn units (well, except maybe Canary whom I haven't tested yet) are having their original skill replaced with the new one at level 6 rather than gaining the second skill in addition to the first. So, for example, Scathach had Trample replaced by Mule Kick at level 6. This is obviously non-optimal and makes the horseborn units problematic at best.

I know there used to be a bug where your horseborn units had their first skill reset to level 1 when they gained their second skill. Maybe in an effort to fix that bug a new one was introduced? Anyone know if there's a way to manually fix this in the save file?