the source of the power does not matter as i tried it with pressure plate (stone), lever, and button.
i tried putting the source 2 blocks away with a redstone repeater powering both the block and dust but the problem still occurs.
The bug may have been introduced in an earlier version but i only found this bug just now, so sorry if some one has already posted about this bug.
I resolved it. Turns out it was a design flaw where the RS dust was powering the block beside it. In version 1.5 you could make zero tick pulse generator like so but visually get a 1 tick pulse. So it is a version difference similar to the old double extender design issues when going from 1.5 to anything newer.
So my bad, sorry for taking up time.
Thx for the reply!