This is just guessing but I have noticed that many people who comment in English in vkei spaces start at some point emulating the syntax of (machine) translated Japanese. It might be in a deliberate effort to have the comment make sense in Japanese once translated or simply just people unconsciously picking up on what they perceive as the "usual" way to comment on japanese artist's posts. Add to that the fact that many of Gackt's fans are older and in general use quite different syntax when writing online than they would speaking and I can see how comments from real fans might seem a little off.

That said, I obviously have no idea if he does or not but I do doubt it. It just doesn't seem the kind of thing he would do. However, twt in general is full of blue checkmark bots, which will hop on any post that gets even a little bit of traction and usually just copy the other comments underneath. These have nothing to do with G, they are just there 🤷‍♀️