From enwiki:

ImprovedWikiImprovment accidentally restored an instance of vandalism that I had just reverted. I've nearly done the same thing numerous times, but the system has alerted me, saying something about "you're reverting a whitelisted user". ImprovedWikiImprovment does not recall a message like that displaying. Is this message something that can be toggled on/off by the user, or is it possibly not notifying even though it should be? Home Lander (talk) 21:13, 14 November 2018 (UTC)

We need to implement something that would allow devs to attempt to reproduce this kind of issue, so that we can go through the exact same rollback request and see what could happen so that Huggle allowed this. There were more than 2 checks that should have prevent this kind of revert.