Potentially related, please see these 2 posts in case you haven’t already:
While someone at Fly look at the back-end, can I ask you to clarify these please… just for my understanding. Of course, they may be just exposing my misunderstanding lol.
There’s 1 instance of the app, but in the next sentence you say ‘servers are in SIN zone’.
Single-instance app, meaning, just 1 microVM within the app?
If so, what do you mean by ‘servers’, plural.
You’ve said the DB connection is stable; what issue(s) are your end users seeing?
The first link above says that ‘App connection idle’ isn’t necessarily an error, hence it was turned into a warning.