I presume you’re using fly logs -a <app-name>?
If so, it only streams logs (from an app’s stdout/stderr, I think) in real-time and doesn’t normally show historical logs.
While viewing logs I noticed lots of prints and errors aren’t shown in logs?
Strange, because this isn’t true at least for the apps I’ve deployed…
You can, alternatively, deploy a Fly app that stores logs in a local Loki instance (ref), or streams it out to a sink supported by Vector (ref). I doubt that these would capture the logs you otherwise don’t see in the fly logs output.