Getting annoying pop up ads when viewing thread - gone again

[A.l.e.x.]

Hello!

Every time I open a thread I get a pop-up (or whatever it is called) ad that covers part if the text and scrolls with the page. No way to close it as far as can see.

I am logged in btw. Please disable this "feature".

Thanks,
Alex

EDIT: just checked - does happen on my I-Pad as well as on my Android LG G3 phone, but not on my computer

EDIT 2: gone again. As sudden as it came...