So it looks like we were working on our last two posts at the same time 
Well before getting into if there’s a bug, note the difference between my code and yours: “t” is the trialClock, which starts over every time the routine is shown. In your case, you’re basing it on the reaction time: if they haven’t responded, there is no reaction time, so it returns None, so comparing a time to None is going to give you strange behavior.
(And I totally know what you mean about not giving enough information, I guess just for me its organization was a little confusing, and I wasn’t sure which problem was the one you wanted solved. But that could just be me.)
So when you get a chance, try out the example and let us know if it works?