"Descriptions" text not showing in Categories (in Posts); Screen Option is on

When I go to Posts->Categories
I see the Name, Slug, Parent all fine…
But then there is Descriptions (on left), but where the editable text box should be there isn’t anything [I do have Description turned on in the Screen Options, and have tried toggling it on/off].
The box with my current text actually appears just for a second when the page loads and then disappears, and then right after that there isn’t anything to click on (no box at all) to allow me to edit the text that I have there. Ack!
I have tested this on FireFox and Chrome, on multiple computers, and with add-ons/extensions off.
It used to work fine, then one day I went to the page and I could no longer edit. Any help would be much appreciated! Thanks!