komalrajsingh, Very nice job so far! Although it seems the problem still exists...
I believe the problem occurs when the sprPlayerPosition is overlapping more than one ElevatedBox. If that is the case, it only works correctly if it happens to pick the taller box. But that isn't always the case.
I changed the code so that it always picks the taller one (by doing a For Each loop by descending ZHeight and then exiting the loop after the first one). I also eliminated some unnecessary code. Like pinning, you are always setting the sprPlayer position anyway, so there really isn't a need to constantly pin it and unpin it. Also, on your "Else" blocks, you don't need to repeat the condition from above (unless you were doing it for readability). In the Jump block you were checking if the sprPlayer is falling, but it is always falling because it is never actually standing on solid ground.
Using the Platform behavior was a creative way of adding a "jump" ability to your player. Someone yesterday in the forums was asking how to do that, and I like the way you did it!
You can see my version at: rieperts.com/games/forum/Xekorn2.capx