Rewarded video AdMob problem with calling video, what should I do?

Question

Android

I set myself ad mob, there are two methods load and show. I collect through the plug-in from Google in Unity for the off lesson.
In show check if(video test.isLoaded()) then show
In the case when you put on one button so that both are called, nothing happens. Tried through one method in which two of these.
We tested another way by calling load at the end of invoke 1.5 seconds and load then loads from 10 clicks, sometimes from the 2nd sometimes from 15-20. In general, tell me if anyone came across?