Observers Emit a Double Pulse When Detecting a Moving Block

Verification builds:
1.2.0.2 Retail

Summary:
Observers still produce a double pulse when they detect blocks being moved by a piston. (A related issue was fixed recently, but this issue remains)

Steps to Reproduce:

1. Have a sticky piston push and pull a block in front of an observer

Observed Results:
Depending on the orientation of the block, the observer will sometimes output a double pulse, instead of one.

Expected Results:
The observer should only pulse once as it detects a block moving in front of it.

Screenshots/Videos attached: Yes

Notes:

Using the examples shown, the Java observer only emits a single pulse when a block is pushed or pulled in front of it.