Notifications delayed until unlock device

Bobsonthegoat

I have had this issue for the last few months where my device enters a "deep sleep" mode on occasion when left idling for any time longer than an hour. The device will not send any notifications until I unlock the device and then I will be bombarded by all of the notifications in that time at once. Any help would be greatly appreciated.

Things I've tried:

Making sure google play services battery mode is set to unrestricted.
Resetting app permissions to defaults and granting permissions to apps upon reopening.

Here is a screenshot of what the battery usage page shows. The gap area is the time where my device is in this "deep sleep" mode.
Image

treequell

Bobsonthegoat I'm not aware of a deep sleep mode, only doze.
https://source.android.com/docs/core/power/platform_mgmt

Push notifications via FCM work fine for me in doze, it sounds like some kind of configuration issue.

Did you follow the instructions on the website for installing sandboxed Play Services? They need to be installed before any other apps that rely on FCM for push notifications.