I observe that network traffic for applications seems to be blocked, or perhaps queued, when the screen is locked, on my MacOS High Sierra 10.13.4 Mac Mini.
The most obvious example I have seen: when running the native MacOS Spotify client, and unlocking the screen after being away for a few days, the client becomes animated - it shows every song I've played on other clients while I've been away from the Mac console, at a high rate, flipping from one to the next, one per second, or so.
This leads me to guess that the Mac caches that traffic, until the screen is unlocked?
What is happening, here?
How can I disable this behavior, and allow the apps I'm running to get network traffic when the screen is locked?