Yes, every category I've tested this occurs on.
Yup, tried to log off an log back on (sometimes my log on attempts take two times now, not sure if that has any impact)
Occurs for me both in Firefox 3.1 and 2.0.0.16 as well as Opera 9.50.
I just noticed that when I return to edit categories, at the top it says "Category edited" as though I redirected back there correctly.
I can post my admin/categories.php file if interested. I did edit my main /categories.php file per the one news mod, but not the one in admin.