That when I check my notifications for mainpage/official sub blogs (like Kitchenette) from a Groupthink page and try to navigate to the subject of said notification, I get that tag error. Even deleting the extra bit at the end doesn't work. But if I go to Jezebel, it does.
For example, I loaded the Groupthink mainpage and saw I had notifications. When I checked them in the drop down, I saw a response to a comment I made on Kitchenette that I wanted to read more of. When I tried to get there, I got the Kinja "page not found" error. I deleted everything after the ampersand in the address and still got the same error.
So I went over to Jezebel, opened the drop down, and clicked on the comment. Took me right there.
Is anyone else having this issue? I've also noticed that I can't usually get to Groupthink from other sites (like if I'm over on Gawker and use the hamburger menu to navigate to GT), but I've seen that one mentioned and deleting the extra bit at the end does work in that case. The notification issue is new to me though.