Vanishing Slicer Data, differing User Experiences

We use a dashboard with multiple interrelated date filters. Today, while using the dsahboard, I adjusted the month slicer by removing checked months to narrow the focus. When I did, those month disappeared from the slicer and could not be brought back.

I've tried refreshing the dashboard page, refreshing underlying data, rebooting my PC, accessing through different browsers, clearing browser history and cookies, and opening the desktop version as well. None restored the slicers to functionality. Oddly, no other users are having the same issue. The same behavior occurs in desktop Power BI.

I'be tried adding a new slicer and associating it with the same data. When added, it shows no data though there is data in the underlying table.

Help?!