After so long lurking around, I finally had to create an account just to try and help out with this wonderful mod. I looked around since you posted the beta and haven't found anything regarding telescopic piston of 1/4 size. Every telescopic piston seems to work fine though. Here goes what I've found. Here I have a series of tests I ran with the different pistons in their starting position. Next I extended all of them under the same group. In the front middle pod I have all the three 1/4 pistons individually. The middle piston (1/4 A section) and right piston (1/4 B section) appear to extend backwards while the C section shows to work fine. You can also see the same behavior in the test behind it trying to push up the parachute with the A, B and C pistons on top of each other, where the A and B actually go backwards just having C push it up. This is reproduced without the parachute on the right hand side. I've tried to reproduce this under different circumstances having the same thing happening. Craft file here.