I too had an issue trying to board a 2 class A380 from the A lounge to the upper deck for a Y seat.

It took us all the way to the bottom where boarding for other economy class passengers had already started and I rang the bell a few times to go back up to the lounge.

I rather just go into the business class lift as the door is the same as the one that economy boards from (upper deck 2 class A380)