This all makes me think that "sleep" on macOS in the past few years is now defined differently -- perhaps an Apple Silicon change? But I can't find documentation that covers this. Buried in a WWDC video, maybe?
I think it was before that. It sounds like you're encountering "Dark Wake". It's only hinted at in a couple of places in the documentation. The "Power Nap" feature is closely related and seems to be more openly acknowledged. But I don't know of any way (for an app) to detect or control when they get triggered. Apple engineers say there's no way to detect it.
Topic:
App & System Services
SubTopic:
Core OS
Tags: