Okay…I think I’ve got it reproducing locally, it’s a multi-process bug. Basically the in-memory version of the settings get changed by the admin in process A, but then a user hits process B with a request and ends up being the one setting the new cache value, and the cache ends up with the old value in memory.
Other site settings get around this by refreshing all settings via MessageBus whenever anyone changes:
I will try have a fix for this tomorrow (it’s my EOD now), thanks for your patience here Moin!