So today I decided to remove a lot of inactive friends upon trying to delete multiple from 1 friends window I have to close and reopen friends window each delete to get to work.
Repeat this problem:
1. open friends list
2. remove friend at top of list
3. try removing the next friend on list (Error)
4. Close friend window
5. try removing next friend at top (works)
6. repeat step 3 (error)
Just annoying bug if you have lots people to remove.