I have a System76 Lemur with the “WiFi up to 867 Mbps”, which is a “Intel® Dual Band Wireless-AC 8265, 2x2 AC +BT M.2 2230 (Windstorm Peak)”.

When I installed Linux Mint and the latest kernel to support the wireless, I found something odd when waking the laptop from sleep mode, it would either hang at the last screen, with the mouse able to move but nothing else working, or, I would get the lock screen, and be able to log in. In both cases, all networking would not work. Then, several minutes later, it would all spring back to life.

Watching journalctl, I could see Network Manager timing out, restarting, failing, timing out, then finally coming up properly.

The root cause of this behaviour was actually the System76 driver. It installs the file /lib/systemd/system-sleep/system76-nm-restart which restarts Network manager when the laptop wakes to resolve an issue in another wireless card. However, that script adversely affects this particular card.

To fix, as root:

chmod 000 /lib/systemd/system-sleep/system76-nm-restart

That will disable the problematic script. Now suspending the laptop works flawlessly.