Piston destroy blocks instead of breaking the blocks.

On creating a automatic pumpkin and melon farm and letting it run for some time on my device I found out that I have not collected any pumpkin or melon, on running some tests (basically going into creative mode and pushing melons and other piston breakable blocks with pistons), I found out that instead of breaking the blocks they are completely destroying the blocks, they are unable to be picked up.I am using Minecraft bedrock 1.9.0.0 on my android phone.