I first got the issue after switching the troop event for the initial summoning to a comment event and having the troop event call the common event, but the issue persists even after turning it back into a troop event. It also persists even if the Enemy Appear event happens only once.
The Troop Event
The Common Event
The only changes I've made to the scripts are changing the variance of the normal attack from 20 to 5, the battle messages, and a bit to change the font. I don't think any of them would be the problem here, though I might be mistaken.
Some other things I did around the same time the issue popped up was create two skills that inflict states (one that inflicts a "slip damage" state and another that lowers agility) and use them in the fight, as well as assign comment events to another couple skills, but the issue persists even if I only use normal attacks.
The Other Two Common Events
Any help in figuring out what's going on here would be much appreciated.