i ran into a very annoying bug in my last game where all the Hippus units became totally inmune to my spells, like it didn't matter what i casted at them or which unit did it it, if it could be resisted it would be resisted everytime (direct damage spells with no resistance check worked fine), i even made the tower of mastery and it made no difference, it made fighting their 95%-105% withdrawal chance horse archers/Cavalary a gigantic pain in the ass, they completely ran over the other AIs with their near unkillable horse archers + heal them with regen combo, another of FFH modmods, Ashes from erebus makes it so units get a promotion after retreating once which gives them a -100% malus to retreat chance which expires after 1 turn, this way you don't have to deal with their near infinite retreat crap but they are still able to retreat and thust retain their purpose. this or something similar would be very good to implement in this mod, keep in mind that the enemy wasn't even using shadowwalk on their units so they could even have had higher retreat chances! which is just silly, makes every other unit pointless if you can spam enough horse archers/cav and its really unfun to go up against, specially since getting highly promoted units right off the bat is really easy in this mod as there are a lot more buildings and effects that give those free xp points for units, so the flanking promotions are trivial to adquiere, i had to make a bunch of cav of my own to fully surround each of their horse archer stacks before engaging it so they couldn't retreat otherwise it was a waste of time to even attack them directly, this was a very unenjoyable way to play to say the least, specially since i couldn't do anything else to cripple them because my spells didn't work on them.
my spells worked on every other civilization in the game, i captured all of the hippus citys eventually and left them only with one city, surrounded it and tried my spells again, it made no difference, 100% resist chance everytime, did the same with the only malakim city remaining and all spells work against their units like intended, later on summoned auric back in the game with the white hand ritual and, again, my spells worked on their units, this bug seemed to affect the Hippus specifically, no other civ not even the barbs were affected by it , it cannot be the Nullstone citadel's fault because i made it myself to deny others from having it, the Crucible hasn't been built either.
also i don't know if this is a bug or not (but it surely seems like it) but some of the Enchantment 3 Artifacts can be destroyed by hostiles mages with the dispel magic spell, but nor in the dispel magic description nor anywhere else does it says that it also destroys enemies artifacts, which it clearly doesn't because it doesn't affect all the Enchantment 3 artifacts you can craft, from what i saw it only affects the shield of balance (force), seven league boots (air), spellstaffs (metamagic) the dahlia band (spirit) and the deasil charm (sun), every other item you can craft with the craft artifact spell cannot be removed via dispel magic (not even the potions that eventually expire by themselves if not used), any item i found via exploring like Mist or the resounding shield were not getting dispelled either, so it only affects these ones, if dispel magic is intended to do this then it should say it in its description, but i don't agree with it doing so (if its indeed intended) as making the items/giving them to units is already a lot of hassle just for a random enemy mage with meta-affinity to spawn and automatically invalidate all the turns you spend gearing up your units with them, with buff spells that get dispelled from my units i can just recast them the next turn, in order to give my units their lost artifacts back i have to, go to the mana node, make it (which takes an archmage turn), give it to my unit if its close (which most of the time it won't be) or give it to another unit which is gonna ferry the items to its destination, which can take a lot of turns depending on how far away your units are, even with the help of airlifting, so its basically not worth the effort to craft them if they can be countered this easily, besides it doesn't make sense for them to work this way, they are items and as such are supposed to behave different than dispelable effects that's what makes them interesting to use in the first place, it also doesn't make sense because it doesn't affect all items, so i really hope this is just another annoying bug and not an actual intended feature
asides from that the mod is in a much better state than when i played it several years ago so great job on improving it all the way through
here's the save where i encountered these bugs