Has there been recent change to penalise aborting a procurement mission ?

I was doing the old faction standing trick of procuring stuff that I coincidentally already had a large quantity of but when I clicked on the ' can't complete this mission now ' in the hope of getting the item I have, I noticed my standing decreasing.

Do this mean that this old trick is no longer an option ?

Its always been like that, Slash.

To build on Luxen's point: You have always lost a tiny amount of standing for taking a trade mission and subsequently aborting it. The amount you lose compared to what you gain for (eventually) completing a mission is so negligible as to be ignored.