I recently tried to use quick reply on mobile to respond to a forum post. However I found the ads hovered constantly over the button to submit my response. Each time an ad ended I got a 0.4 second window to hit that button before the alternating ad began. I refreshed the page in case this could solve the problem, but it resumed.
The workaround I used for the problem was to use the rich text function. After that the button to submit another quick reply was still blocked, but I no longer needed to post.
I had a bit of spare time so I leaned more to being baffled and amused by the absurdity of it, rather than disgruntled.
However I hope it is something that is easily fixed if it affects more forum users.
Best of luck!