Filter Gallery not working - depending

Hi All,

yes, I've seen other posts regarding the same topic. 

Yes, images are in 8bit, RGB

But when going to Filter > Filter Gallery .. nothing happens. (Filter Gallery is NOT grayed out!)

And here is the kicker: closing PS > restart > now Filter Gallery works!! ... same image.

After that .. trying on another image ... NOT working.

Close PS > restart > works!! 

What's going on??

(yes, CC and PS latest version)

Thanks in advance