Tactical enhancement spells (like Evade, which gives +1 Dodge rating) can stack infinitely as long as you take the time to cast them. This isn't a problem with something like Evade, but Guardian Aura (for example) gives +50% Dodge rating. Get a couple champions casting that on your main combat unit, and things get ridiculous. I had little trouble getting blasting past 300 Dodge with my Sovereign, with a couple imbued champions to spam Guardian Aura, which reduced all enemy hit odds down to only a couple percent. I proceeded to totally roflstomp the AI, which had no means to deal with my night-unhittable sov.
The problem is that some tactical bonus spells, like Evade, seem extremely weak even when stacked. Others, like Guardian Aura, become completely broken when spammed (note that you can also spam de-buffs like Blindness, too, but Guardian Aura was even more efficient). I assume that this stacking is unintentional, since you can't stack normal enchantments, but either way there are some spell balance issues that need examining. These buffs are even cheap mana-wise, so the spam isn't that costly.
Note that the issue I'm worried about is less the specific spells and mechanic that I abused (Guardian Aura and Dodge), but rather the overarching mechanic that permits tactical buffs and de-buffs to stack. Is this working as intended, or is it a glitch?