I just went into the Thalmor HQ in Solitude for the first time. I have to wonder what the artists were thinking when they were decorating the place. Imperial Banners in the Thalmor HQ? I would assume the Thalmor would have their own banners.

When I came out, having just gone "wait a minute," it finally struck me that the decorations around Castle Dour are also bizzare: The emperor's tower and Tullius's HQ have Solitude Banners rather than Imperial ones.

There is a tad bit of illogic infesting Solitude. I suspect it is Sheogorath's doing.

...There's a Butter Elf HQ in Solitude?

yup, close to castle Dour

It part of Castle Dour. Normally its locked but this time it was opened so I decided to go in and check it out. Its just up the stairs from Tullius's HQ.