>>775066I'm pretty sure when most people say "drugs" they aren't implying she was going full Breaking Bad or some shit. It's not exactly a secret that Japan is hard as fuck against drug use and even something as simple as recreational weed smoking can end a career. Usually speaking, when someone says it was probably drugs they aren't digging for some delicious rrat that'll feed the shitpost machine. They're trying to find one of the few rational reasons something like this happened.
The only real facts we have, assuming you take what's been said at face value (both in the last day and in general) are that GYARI is generally laissez-faire about the whole managerial side of things, the other girls are still friends with Monoe and are heartbroken that it's had to end this way, this was due to an issue that's been going on for a while, and the decision was made days in advance.
The business model of VOMS doesn't really leave much room for this to be about corporate politics/fraud, so it's almost inevitably an issue with Monoe's character as a person yet an issue that the rest were willing to either overlook or try to help her overcome until now.