they may want to remember that the rooster crowed once before Peter denied Christ three times in Mark,
Peter would be the only one who would know first hand, and how could you forget something like that.
I believe the fact that the word ;Twice; being left off would not be a contradiction but only a detail not aware of by the other writers..
For me it’s just a lesson in not hanging on every word in our bibles as “gospel”. One needs to remember that these books are VERY old, cobbled together, and put their by men. They are VERY helpful and instructive in living your life for Christ, but not to be worshiped. Christians don’t worship books. We worship our creator.
A bible is a bunch of books written by men. These men were all inspired by God. They are still written by men. In fact, that is one of the things that makes them “real”.