This is very confusing: when I run it in Chrome in r175, I don't see what you've posted screenshots of. I see this:
Since this does not appear to match any of your images/descriptions, I don't know what to make of it. Also since we did not change any collision/event related code in r174 as far as I can remember or tell from the changelog I am at a loss as to what we could have modified that would have caused any change in behavior here. On top of that the events implement a relatively complex algorithm with function calls, arrays and loops, so it is very difficult to debug.
To help me have a chance at figuring out what is going on here it would be invaluable if you can:
1) reproduce the problem without requiring any user input at all, so I can see exactly the setup you have
2) simplify the events as far as humanly possible while still demonstrating a change in behavior - ideally <5 events
3) identify the specific event or feature that is now working differently, and explain precisely what the difference between the versions is