From doing a little poking around... Apparently MacOS, at least in the previous version to Sequoia, had a feature called Power Nap. That would let your battery powered Mac laptop periodically check email when it was sleeping.
I *think* that was enabled by default. But don't know for sure, now not having a Mac with an OS previous to Sequoia.
Here's an excerpt from an Apple document (link below) that shows how to enable/disable it. The problem is, that doesn't seem to be the case with Sequoia. You're supposed to see an Enable Power Nap pop-up when you do the following:
- On your Mac, choose Apple menu > System Settings, then click Battery in the sidebar. (You may need to scroll down.)
- Click Options, click the pop-up menu next to Enable Power Nap, then choose an option.
I don't see the above option at all in Sequoia.
Here's a link to the Apple document:
https://support.apple.com/guide/mac-help/turn-power-nap-on-or-off-mh40774/mac#:~:text=When your Mac is asleep,Updates other iCloud events
I'm wondering if there's a bug that left Power Nap in the ON state from the pre Sequoia OS.