The stoppers on my Ti Birdy from Pacific Cycles are the same as on the Birdy 3 but with a completely different adjustment, much longer out on the Ti Birdy.

There are two stoppers on the Birdy, one fo the fold of the rear arm, one for the seatpost, which stopper is screwed in all the way on your Birdy ?

On my Birdy 3, the one for the seatpost is screwed in all the way and has no adjusting nut, the one for the rear arm folding not and has an adjustment nut.