Vandoren v16 alto mouthpiece

I've been playing a Vandoren v16 A8 hard rubber mouthpiece on alto for about a year and a half, I bought it new.
I play with traditional Vandorens #3 but no matter what reed I use I cannot get a good seal, i suspect that the table is warped but that usualy happens on much older mouthpieces and it appears to be OK visualy.
Has anybody else had this problem ?
The A8 has medium-short table, maybe that's relevent