I don't know if it happened in earlier versions too.

I made a redstone circuit and placed a commandblock at the output side of a conductor which is next to a redstone wire (view first screenshot)

What I expected to happen was...:
As the commandblock should only receive redstone signals and output commands, the redstone wire should be left with the currency it had before

What actually happened was...:
Instead, the redstone wire got powered by the commandblock

Steps to Reproduce:
1. place a repeater or a conductor
2. place a commandblock at it's output spot
3. place redstone wire next to it