I can understand that a priest who hears confessions (and gives absolution) in more than one language, might have more difficulty. Around here I’ve only heard one form of absolution, but that’s not to say that some of the priests might not hear confessions in other languages.
Even so, I think it would not be that difficult to memorize the words of absolution in more than one language, or at least carry a card with the proper form. I have a hard time thinking that a priest can actually forget the words of absolution and be forced to ad-lib!