Probably the same issue.
I have an IFTTT (or as it is now called, IF) recipe triggered by my contact sensor. The recipe is activated 3 times instead of once.
I have my own SmartApp triggered by the same contact sensor. It also gets triggered 3 times instead of just once. That happens even if I have Push Notifications turned off in my SmartApp.
I also have the Dropcam “Photo Burst When…” app triggered by the same contact sensor. For some reason, that app fires just once.
So, it does seem that the problem is limited to particular SmartApps. Go figure.
I really hope the SmartThings guys come up with a fix for this quick. This is a new problem, that got introduced not more that a few days ago, I believe.