Not more than 10 minutes, but both transfers were about 2 minutes long. This could be important.
If you exit a station within 2 minutes of entering then a maximum fare will be charged. That's £5.40 off-peak. If you enter another (or the same) station within 45 minutes then the maximum fare is cancelled and a new journey started. Most people using the cut through on Oyster PAYG or contactless will be using the same method at Waterloo East so it isn't a problem.
If you exit between 2 and 30 minutes after entering then you are charged the minimum fare to travel from that station. I have a funny feeling that the minimum fare from Southwark is £0.00 because of the cut-through aspect. The journey history shows times accurate to a minute. If the times (H:M
) were 17:00:15 and 17:02:40 then that is more than 2 minutes but rounds to 2 minutes on the display. But 22:41:30 and 22:43:25 is less than 2 minutes and also rounds to 2 minutes on the display.
I would expect the helpdesk to refund the charge if you explain what was going on. I'd be interested to know if the reason is down to over/under 2 minutes.