For the first utterance, if punctuation prediction is performed first, it might break the utterance both before and after "uh" so that the second-stage disfluency prediction will treat the whole utterance as three sentences, and thus may not be able to detect any disfluency because each one of the three sentences is legitimate on its own.
for the second utterance, if disfluency prediction is performed first, it might mark "I am sorry" as disfluent in the first place and remove it before passing into the second-stage punctuation prediction.