On Wed, 1 Mar 2017 10:33:01 +0000, Roland Perry wrote:
My own classic Oyster occasionally flashes up a message about "your card
is about to expire", or something similar (if they want people to read
it they should display it longer). But it isn't, and the next gateline
won't repeat it. Mystery glitch perhaps.

That appears to be a bug with some of the gate software. The FOI obtained
copy of Ticketing & Revenue Update that started this thread has a Q&A
about it on page 13.