It doesn't matter if YouTube and Piped links may differ: just leave posts that already provide a Piped link alone.
Sample post: https://sh.itjust.works/post/19987177
What's more, it duplicates essentially the same thing, so it mght be related. Regardless, if any Piped link is provided, bot simply should refuse commenting. Otherwise, what we get is an unnecessary promotion of the central instance - then how is it better than YouTube, besides having less tracking?