I agree and a case has been opened (#2005359249).
But, sincerely, the answers I've received until now and after more than 72 hrs are passed I did not like at all.
From support first they answered that they will low the case to P4 and then, that, as stated in Release Notes, this is a change of the new produtct.
I've answered them that we're really disappointed first because customer has the migrations locked and that the RN has nothing to do with this that is, quite really, a bug.
If I run a frequent backup (hourly) based only on "archive" I did not expect to have all the db altered for backup as a full one! This is causing issues about performances, time windows, unuseful snapshots and so on.
I hope that they will take care about this,
Regards