Fixed as of 0.15.1 full
In MCPE 0.15, there is a "version exclusive" that pistons can push block entities (such as furnaces, chests, rails, other non-activated pistons, daylight sensors...).
Only blocks that can't be pushed are: bedrock, obsidian, enchantment table
The exact thing happens on my devices ~ Asus Zenpad Z370C and Alcatel OT 6010D Star