Never heard of it. The only changes to the A2 model AUG over the A1 was a different charging handle and a roller on the top rear of the bolt carrier.
Same barrels, it seems. I can't tell the difference. The gas piston cylinder assembly is extremely beefy.
If there was a problem with the AUG's gas system, I believe that I may have heard of it by now.
Sorry, wrong gun. I was thinking of the Enfield SA-80. That one is one mean bullpup!