Maintenance for the week of April 6:
• [COMPLETE] ESO Store and Account System for maintenance – April 9, 9:00AM EDT (13:00 UTC) - 6:00PM EDT (22:00 UTC)
[EXPLOIT / BUG] Imperial City Queue
Patch Notes:
There is no longer a limitation when queuing between similar types of campaigns, i.e. a Cyrodiil campaign can now be queued to from another Cyrodiil campaign and Imperial City campaigns can be queued to from another Imperial City campaign.
and
You cannot queue for another campaign while in Imperial City (includes sewers and districts) if you have 100+ tel var stones on your person.
I have found you can queue for a different instance of Imperial City regardless of how much telvar you have on your person. Given the above statements this is most likely an bug.