Like the title says, pistons won't push players out of the way near pressure plates. Instead, the player gets teleported behind the pistons. (The piston the player gets teleported behind seems random.)
Steps to reproduce

1. Build a 1x2/2x2 set of pistons, deactivated by a pressure plate.
2. Activate the pressure plate.
3. Stand between the pistons while they are open.

What should happen:

The player should be pushed out of the way of the pistons.

What actually happens:

The player gets teleported behind the pistons.

Watch the video I've attached to see the bug (ignore the watermark, I had to shorten the video to meet the size requirements.)