I'm not using C3, so can't open the c3p to check, but is this the same one where the player is continually set to the same X position?
If so, in the event that sets X postion, add in a Player Is On Floor condition, so it doesn't do it while the player is jumping/falling, that way the blocks can push them back.
It is this atm imgur.com/a/vGwGb (as suggested to do in another forum post)
The crossed out bit above is the default it was at, which was using the endless runner template.
Not sure exactly what you mean, first game for me!