UC phasing bugged for lowbie

My level 30 mage is doing Legion and she is a scribe. She has acquired a quest called The Plot Thickens, which requires that I speak to an NPC in the UC. Problem is, this NPC is in the original UC.

For some reason, although I have not played either BfA or Shadowlands, the UC area is phased post-Shadowlands and I cannot get into the UC.

Moreover, although I can see Zidormi, she offers no option to phase the UC/Tirisfal Glades back to its original form.

I reported this in-game, but the GMs and CSRs were unable to resolve it. They asked that I report it as a bug. Apparently, the UC should not be phased for this toon, but it is.

Hope you can fix it. Many thanks.