So, got the fight against the first giantess after god knows how long, said "yeah I can take her down, ezpz".
She goes something like "The weak will feed the strong, such is the cycle of life." and next turn I think it was a skill called 'Origin of Growth' and this error message popped up.
Now I imagine that there's some RMMZ shenanigans happening that's preventing the skill from going out (either from int overflow or ??? is an invalid name for the user).
As for any other info that may or may not be useful:
Regular difficulty, 5819HP on PC with 126728 Height at the start of combat.
??? is at 10000HP and 151579 Height at the start of combat, but gains 9M Height once the Mass Absorbtion skill is used.
Cruel Destiny, Reality Slice and Meteor Storm are fine and work properly even at 9M+ Height. Mass Absorbtion ALSO works at 9M+.
With some luck on my side, I did manage to beat her with True Stomp from Galatea - Tall (alongside getting her height with my own First Giantess card) and had it "upgraded" lol. Was not expecting it, I was (and still am) trying to push for Dianne's stages/story but it's so much waiting and it feels like I'm only halfway done with that one.

