Possibly though there’s even a community council post about it:
That mostly talks about people who exploited to get rid of the xp buff and power leveled themselves or others but some people claim they didn’t do anything besides running TW on twinks.
I think it’s possible you could have people false reporting twinks out of spite or for speed hacking or something that didn’t understand the mechanics. It would be on Blizzard for acting on false reports still if that was the case.
I’ve done a ton of TW dungeons on twinks in the past couple weeks though and nothing happened to me.
According to some threads on the xpoff forums there was also an exploit people were doing to get 100% drop rate in timewalking dungeons. Nobody mentioned doing this in the ban threads but that seems easily bannable (though it’s easy to do if they haven’t fixed it yet and some people might run into it accidentally). You’d have to do it intentionally though to do it repeatedly.