Able to dupe Powered & Activator rails, by simply pushing a rail onto an invalid block with a rail of the type you would like to dupe next to it (this rail must be powered).

The rail being pushed must be facing the opposite direction of rail next to the invalid block.

I can actually explain why this happens:
Basically the rail gets pushed onto the piston, then tries to connect to the other rail, it will then pop off since it cant be on the invalid block, although the rail then gets powered by the rail it was trying to connect to, causing an instance of it to still be there, which then also pops off.

I should also mention that if the rail is facing the same way, it will get removed... (also bug)

Here is my video on the subject: https://youtu.be/5hcClvAKtM4
(I used a piston as the invalid block in my video)