I think the mechanics that cause it is because the drain takes the player down to 1 ATK and 1 DEF rather than the 21 ATK and 16 DEF that Ethan starts with at level 1. I'm pretty sure that if players stocked up on 75 Lava and Frozen potions they wouldn't have to lose to get to level 5... it's just that the potions would only give +1 each at level 1. I'm thinking the EXP fix would only make it so that Ethan can max out on ATK and DEF at a much lower level, if the player was inclined to do so.Fair warning that Cobra's drain is being adjusted to store levels as EXP, meaning her "exploit" will be less effective (you can still do it, but you'll only be receiving the EXP for levels 1-5 rather than 5 flat levels).
For what it's worth, using Cobra as a "reverse-battery" to get a few levels by being her bitch is intended, but the current implementation is obviously neither lore-friendly or particularly fun (players feel pressured to do it because it's so "efficient", then feel the game is too easy once they do it).
When this change goes through, her EXP will automatically be calculated when you load the game on the new update. Thus, if you don't want to lose your "hard work", just Tribute everything to her before moving your save to the new version.
A bug causing her EX mode to be way too strong will also be fixed, in case anyone ran into / was wondering about that.
Thanks for everything!