I just tried to revoque https://fr.wiktionary.org/w/index.php?title=stupide&diff=25583256&oldid=25583252 , but revocation has failed for an erroneous reason: "Changes already revoked / Last edit made by JackBot" which is not the case, since no one has revoked that edit.
The anon user has rollbacked already his previous change, see this diff https://fr.wiktionary.org/w/index.php?title=stupide&type=revision&diff=25583256&oldid=24793944
In this case the content of the last version is equal to the content of JackBot's version and that than there is nothing to rollback.
If you want undo the last change of the anon and keep the previous one, you have to use undo action, because rollback action rollbacks to the last version which is not from the current user.
Oh... I was using a third-party tool to patrol, and I realized that it changed my habits—that is why I did not realize that the changes were actually still patrolled. So, my mistake! Report canceled.