As this bug is quite complicated, I will talk about how to recreate it first. Place two redstone dust, then a block in front of the redstone, and a piston in front of the block. Place a piston next to the redstone dust which is next to the block. Power the redstone line at the redstone at the back, both pistons get powered. This is because pistons do NOT redirect redstone, but the texture shows that it does redirect redstone and power the piston at the same time.
Linked issues
Comments 3
+Specialistol not really 'Wrong side', instead, piston just did absolutely nothing to the redstone dust line, but just making the texture look like that piston redirects redstone and also powering the piston, but whatever. Thanks for your reminder.
Closing as a duplicate of MCPE-16892
If you think this is a separate issue, please provide screenshots that clearly show the problem.
This is a duplicate of: MCPE-16892 (It is a bit difficult to find since there are too many different ways to describe the problem)