Sucker Punch Parental Bond

I noticed that when Mega Kangaskhan uses sucker punch, he only hits once. His second attack doesn’t hit and instead says something along the lines of “but it failed”. Is this an intended interaction or a bug?

I’m guessing its a bug where the priority from Sucker punch negates the second Sucker punch.
It might be something like sucker punch can ONLY attack first, so with the first sucker punch hitting, the second one won’t, because a move has already been used in that turn.