Android Question confusion of using B4X ADMOB LIB Interstitial AD


Licensed User
I'm confused about the use of B4X ADMOB LIB Interstitial AD。
normally, the display and event flow of Interstitial AD are shown as the following figure.


But, when user click Interstitial AD, the flow like this .
In this scenario, user can click Interstitial AD many times. Step2 and step3 will run many times.
I think these clicks will be considered as Invalid click.

So my confusion is :
1 Admob Lib event why not Unable to respond in real time?
2 How to prevent users from repeatedly clicking to produce invalid click?
3 I find in play-services-ads-lite\19.4.0 jar, there is destroy() event.
so If a user clicks on an ad, it will generate an ad Click event.
and if app respond to the event in real time, And execute AD.destroy() in the event function.
Is it avoid the above problems?