Ok - maybe slightly weird 'feature' of Oyster, or just me and the DLR
captain being stupid...

Today, I had to pop home to pick up something at lunchtime. So, got the DLR
from Bank using my Pre-pay Oystercard to swipe in through the gates.

Got to my stop on the DLR, walked out and swiped my card again to say that I
was leaving - and checked that it actually did register.

Picked up what I needed to get and literally got back to the DLR for the
next train back. Went to swipe in again but this time it still said 'exit'
instead of 'enter'. Thought that maybe I was going made and had misread the
machine when I left and it hadn't swiped properly on the way out so I had
just registered my exit and not entrance onto the DLR (are you all still
with me?). So, I swiped it again. And it still said 'exit'. After a third
time it said 'Seek assistance' (which is great on an unmanned DLR station).

Anyway, when the train came I was lucky enough to be at the door with the
DLR captain/ticket inspector so I asked her to check the card. She checked
it and said that it said it was registered as a 'continuation of exit' but
had no idea what that meant. As I didn't want to get stuck at Bank, she
reset the card register as the start of a normal single trip.

So, does anyone know what this all means and what would've happened when I
got to Bank? Would it have registered the journey as Bank - Bank and only
charged me for a zone 1 journey (instead of the zone 1 - zone 2 journey
that it really was).