Same happened to me.. cap would not open lucky enough had a 60 mile range so on way home called into the dealers where I bought the r1300 gs from.. tech said.. I know what's wrong you have fitted a sw motech quick release tank bag.. told him I've used this sw motech tank bag on 2 previous bmw r1250 gsa and r1250 rs both with the same keyless cap.. so he removed the tank bag and the sw motech tank ring and replaced the 4 bolts with oem bolts and the cap opened first time which he did 4 times.. I help myself to a free coffee and a nice piece of cake.. then noticed on a new r1300 gs triple black was a genuine bmw adventure Large expandable 11 to 16 ltrs tank bag olive with black accents look well on the triple black also designed for the gs sloping tank was surprised when he said it's on sale for less than half price for £119.00 with harness tank attachments "which are sold separate" he even fitted it while I had another coffee and cake

I still use the sw motech tank bag with the the sw motech quick release plate seat attachment on my speed twin. still not sure if the cap would not open due to the sw motech tank being fitted or I did not use the correct r1300 gs opening procedure stated in the owners manual

but all ended well as the sw motech tank bag on the r1300 gs didn't look right with the sloping tank.