I don’t remember ever seeing a button labelled attack but this showed up while I was attacking a gym yesterday. No hitmonchan were harmed during the incident because there were none in the gym or in my team. Everything was frozen when it happened, it’s all over weirdness but “ATTACK”…piqued my imagination.
Well your charge move is there, so i assume its just placeholder text.
Report it to Niantic. I have received this glitch also.