From what I can tell, the "good"/edited MTL only contains the script for the three scenes that work (the first two and the tentacle training scene) because if you look in the CommonEvents.json file in the data folder you'll find all of the dialogue for those scenes but you can't find ANY data for any of the other scenes. It's also nearly half the file size of the MTL that actually works for all the scenes, as well as only having 650k characters vs 1.2 million in the working one. For some reason whoever shipped that version only had a script for three scenes and I suspect that's why none of the others load from the gallery and also why the game basically crashes when you get the first red orc training scene.
I think you could play the game just fine with the "fixed" mtl if you just use the CommonEvents.json and maybe CommonEvents_bk.json (not sure what's in this one) from the bad translation and the rest of the game will have the better translation but yeah it's a bummer that all of the events are broken with the better one.
I don't know crap about RPGmaker so if I'm wrong about anything I apologize, I just thought there might be an easy fix if something got messed up somewhere so I was looking around. Unfortunately there is straight up no text for any of the events scenes in those files, not even Japanese, so I'm not sure anything can be done. I've loved this circle's games for a long time, since TID 2, and it's such a shame they're plagued by these awful machine translations.