The Cataclysm Timewalking event is advertised in the adventure guide for a level 42 character that can’t even queue for it because they are in Chromie time, but it is not made clear Chromie time will remove you from eligibility. It just sends you to the LFD specific dungeon list when you click “join group.” Another level 42 character not in Chromie time is able to queue for it, but the support article states that Timewalking dungeons require level 50.
Either way, the support article is inaccurate and should include being in a Chromie timeline as an additional reason why one couldn’t queue, and the level should be adjusted to reflect the current level requirement if it’s been lowered. Since level 50s can’t be in Chromie time, it makes sense that this may not have been an issue before if 50 was the original requirement.
This may include additional bugs in-game, as I’m not quite sure what is intended.