I have searched this and found many similar dupes, but this one relies on powered rails bedside the hole in the dupe machine. This dupe can dupe only powered rails.
It works on survival and adventure and creative (tho creative doesnt count).
Also the obsidian block seen, is just being used as a block that cant be pushed.
I thought it was a dupe in 13w10b but I was in Creative (derp = me) not a dupe in survival. It only affects 1.4.7 in survival it turns out.
Linked issues
duplicates 1
Attachments
Comments 10
After some more testing in the snapshot, I can confirm it is directionaly affected. I cannot reproduce it facing north or south, as a 1 tick clock from a comparator doesnt not spas a piston facing south or north but when the 1 tick clock is from repeaters I can reproduce it facing north and south.
No matter how hard I try I cannot reproduce in 13w10b. Note that this was fixed in MC-1619.
I've figured things out now. its was only a bug in 1.4.7 whilst in survival that only worked with powered rails. I was getting a dupe cause I was in creative on the snapshot. So I have updtated my affected versions. I am a derp...
Resolving as duplicate of MC-1619.
Cannot reproduce.