So a couple weeks ago there was a bug that would make your crusaders randomly refresh their buffs, adding a good deal of lag to the game.

It would seem this bug is back, but in a slightly different way. It occurs when your DPS changes from a monster attacking the front row.

Example: My formation has Thalia and Jason in the front row. When a monster reaches Thalia, Jason's ability that boosts DPS activates and the buffs refresh. Additional monsters do not change this, but when the last monster touching Thalia dies the buffs refresh again as Jason's DPS boost wears off.