Piston Disappearing Bug.

Sometimes When You Make A Double Piston Extender Like The One In The Picture Attachment You Have To Lengthen The Delays Due To Different Redstone Programming In The Pocket Edition Versions Of Minecraft.
There Is A Chance That On retraction The Main Part Of the Piston Will Become Invisible And It Will Leave The Piston Head As Shown In The Picture Attachment I Have Provided.

Because I Am A Minecraft YouTuber Who Makes Redstone Contraptions This Deeply Annoys Me Because Of Some Of My Contraptions Start Bugging Out Like This.
If You Can Sort This Problem I Will Be Massively Great-full And So Will All The Other Minecraft Redstoners.
Thank you.