There have been a lot of Watch List problems here lately. Perhaps it is related to some of the technical 'fine tuning' that is going on, or a glitch in the system. Maybe there are going to be changes forthcoming, like when they added that feature where after we delete items we get the dialogue box asking if we are really truly sure we know what we're doing.
One thing you can try, - never hurts, - is to delete your cache and cookies (temporary internet files) on your computer and then restart. That seems to clear up a lot of problems for many people.