However... it can also trigger new behaviour because programs / services run for longer than normal because deployments aren't being refreshed as frequently as normal.
I don't think it's even that much of an edge case. We've definitely had memory leaks on all sorts of services just because they were running longer than usual without a deployment.
This caused at least one outage in my career. Memory leak caused every single app server to crash in the space of a few hours on new years eve; regular deploys had been hiding it.
This is unfortunately all too common, but it can at least be solved with a simple restart - and truly fixed after the holidays, which is much better than a 4h debug fest because of a typo in some code someone wanted to quickly get in before the holidays.
We had a problem where HikariCP was slowly recycling db connections but failing to open new ones. Guess what happened when the app ran long enough the final conn in the pool closed...
I get it, we're hackers, we like to think of edge cases and are pedantic as hell. But pedantry and edge cases aren't always useful in conversation.