I think that this is a very serious issue. Imagine a bank where 0,5% of all transactions get lost and those customers loose their money. That is how serious this problem is. It makes customers not want to buy apps on Google play, because the purchasing process is not reliable. This is very damaging to Android developers and to Google Play, especially since the purchasing rate is already higher on iOS Appstore. This issue makes me not want to use
IAB until it is solved. I am so tired of getting blamed by customers for an error that I am not responsible for.