A rotation will invalidate the old keyset (effectively same thing as revocation)
Discussion
Maybe I need to read more about how frost works.
How does that work, documentation?
This documentation seems to decribe it more (answering my own question, partially):
From my understanding, 'invalidate' or 'revocation' are not the best descriptors. The old keys could still produce a valid signature, it's just that the participants, with new keys, choose to no longer use the older keys, though they may still be stored. That refreshing of the keys wouldn't however require a new public key to verify.