Thank you for playing my game! And that is really strange? I have yet to hear of "X" causing such an issue, but I will try to see if I can find an issue to that.
I have downloaded the game from itch.io onto my computer and pressing "X" doesn't seem to cause any issues, do you happen to remember what the error message said or have a screenshot? Maybe I can find a way to fix this and re-upload it so this won't happen again. But I do apologize for that, sorry! And I like you too, friend!