Mine is working, but here are some quick steps to try.
Silly, but make sure you are logged into MTurk, and refresh the dashboard page you have loaded
Ensure that you are using the correct link for PC -
https://worker.mturk.com/requesters/PandaCrazy/projects
If all else fails, you can go to tampermonkey and delete the script and install it from scratch (different than just re-installing it)
I could be wrong, but I believe that is the doings of AMT themselves. IIRC
@SarahAshlee90 said it was actually causing some grief in regard to scripts. Also, from what I've noticed, not only do you get the number of HITs, but when you are working on a HIT the HIT title goes in the tab now as well. I kind of have been liking it so far, but it doesn't provide that much benefit. I feel bad that it's causing problems for some people though