Well. I've tried to test the sticky pistons. Then found out that the sticky piston cannot push or "grab" slime blocks. Didn't test the regular piston actually. Not sure if this is a bug or not.
Device: LG Zero/Class (LG-H650E)
MCPE-14601
Sticky Pistons cannot push slime blocks
Resolved
Works As Intended
0
(Unassigned)
Unconfirmed
Phone - Android - LG Other (Specify in description)
Android 5.1.1
0.15.0 Beta build 1
Retrieved
This issue Works as Intended. If you have a feature request, head over to the Minecraft: Pocket Edition Forums.
The slime block will attempt to pull the grass block it is connected to along with it, which is impossible since it exceeds the maximum amount of blocks that a piston can push.