Since the last patch, I've been getting a lot of instances where getting caught pickpocketing disables the BoW ability. I can still steal, but the X prompt doesn't come up, so I can't assassinate. This has happened on multiple characters, and /reloadui and zoning do not fix it. The only fix is to log out to character select.
RIP Bosmer Nation. 4/4/14 - 2/25/19.