which probably means that somewhere in some file there's a localisation error that is attributing horse archers the status of light cavalry.
That file would be 00_special_troops.txt where it reads
Code:
horse_archers = {
...
base_type = light_cavalry
}
I believe that's where the problems come from. Actually, things started to go bad for Byzantium and horse archers when Rajas of India was released and they added elephants, but something in the game couldn't handle an extra troop type being included, so they replaced the last troop type, horse archers, with special troops. That was good because now we have camels and elephants, but horse archers have been broken ever since. Right after this happened, cataphracts started rolling gray wall, which was way worse. Thankfully, that got fixed. Harass and raid tactics firing have been reported for a few patches now, but to no avail so far.
Another annoying thing about this switch to special troops is the fact that previously cataphracts looked totally bad ass, but that will probably never get fixed, since they have to make the 20 elephants appear in the Indian retinue along the 200 archers so their graphical factor has to be way high in the defines. Good for India, I guess, but some more love for Byzantium wouldn't hurt.
In fact, I started a thread to try to brainstorm solutions for the harass bug so those of us who don't care about achievements can play happily until Paradox decides to fix it. I actually found a partial solution, but it only worked when the other army didn't also have horse archers. I don't have much experience with modding and I don't own Horse Lords so I can only do limited testing myself, and I can't figure out what is missing. It would be really nice if we figure out a fix.
The thread is here:
https://forum.paradoxplaza.com/forum/index.php?threads/lets-try-to-fix-horse-archers.968612/