Paul Corfield wrote:

But they might (and I don't know for certain) set the journey as exited
which would cause an interesting conundrum at Liverpool St. This is
because they usually do the opposite to the last entry or exit
transaction. The OP would have entered at NOG and "interchanged" not
exited at the JLE gates. Now it is possible that the validators are NR
platform specific at Stratford so Liv St bound are always entry and
those to Ilford etc are always exit. However that is not my
understanding of how Oyster validators work.

Also the Ilford bound validators are on the same platform as the eastbound
Central Line - so a passenger could be just as easily continuing onto say
Wanstead as going to Ilford.