It's not common, but I think there is only one A380 gate at AMS (Gate 9). There is a lot of work currently going on, so Gate 9 is sometimes closed.
When it happened to me, we parked up and then were pulled into a contact gate.
Why hadn't the passenger with crutches requested assistance? OK, you may have expected a contact gate at AMS, but there is a lot of bussing at DXB.