I've just looked at the Journey History for the Oyster card my partner uses.

He went to Milton Keynes via Euston on 23 February, returning the same
day. His morning outward journeys (bus & Tube) are given correctly. The
evening return is totally absent. Next use of the card suggests £5.50 in
total was deducted for that day, which should have been capped at £5.40
(Zones 1-4 Off-Peak).

I'm not going to chase up 10p. Does anyone know why there was this glitch?

--
Helen D. Vecht:
Edgware.