Teester
This appears to have been done in changeset #52546473 (https://www.openstreetmap.org/changeset/52546473) by Polyglot (https://www.openstreetmap.org/user/Polyglot).  I've left a comment on the changeset asking them to reply here.

Numerous route relations appear to have had one of their route directions changed to this route (which is Route 47 - Belarmine - Poolbeg St - https://www.openstreetmap.org/relation/1222860).  Hopefully there is an easy way to revert the unwanted changes.