Hello Itan
It seems I am still having the problem. I uninstalled the mod completely and reinstalled it again. Started a new 2-turns-per-year late campaign.
Sadly my units changed again. The cavalry unit I started with turned into Irish Brigade infantry, and some irregulars changed to line infantry, after ending my turn.
Also, when I bought 12lb foot artillery, it turned into 6lb horse artillery on the next turn.
It's really a shame that I am experiencing this bug, I would really like to play it properly.
Thanks for the continued effort!