Esper Terra vs Humbaba Battle

Terra is suppose to be in permanent esper form during this battle, but she appears in her normal form instead. Checking the status menu within battle (I named the status), she's definitely under the status. She has the status, but doesn't have the sprite. This is the first I've ever encountered this "bug/error". Outside this battle, Trance work as intended. Anyone got any ideas why this is happening? Would there be anything such as 0 AP (Trance bar was depleted or at 0 before losing Terra in the World of Balance) that could explain this?

Or is this "special battle" or condition handle somewhere? I've check the scripted battles within hex, and compare mine to a vanilla rom and there was nothing different. Last time I check, this battle worked as intended, permanent esper Terra was working and present.