SweetKick

@gprovost I am running OMV 4 and the watchdog service was the issue.
I reverted back to the default WoL configuration then adjusted the existing helios4-wol.service file with the "network-online.target" changes, I see the Wiki was updated as well.  Creating the two "openmediavault" files with the contents from your commit link and giving them execute permissions solved the issue.
 
Thanks.

@SweetKick Regarding the issue of WoL not being enable at each startup, there is effectively a timing issue that seems to be new... the eth0 interface is not yet ready when helios4-wol.service is triggered. I'm going to look at this and see how to fix that.
 
Regarding the other issue where your system reboot 1-2 minute after the system has been put in suspend mode, my guess is because you have installed OpenMediaVault. OMV install watchdog service by default. When the system is put in standby / suspend mode the watchdog is not stopped, therefore since nothing will be kicking the watchdog in that state, the watchdog will reset the system after 60sec.

The workaround for now is to disable watchdog service.
 
sudo systemctl disable watchdog  
Note: you will need to reboot after you disable the watchdog in order to ensure the watchdog is stopped.
 
This also something I was supposed to investigate, in order to see how to make systemcl disable / enable watchdog before / after going to suspend mode.
 
Edit:
Actually I forgot but I did work with OMV guys to fix the watchdog / suspend issue here : https://github.com/openmediavault/openmediavault/issues/343 But the fix only made to it OMV5.
You can add manually the tweak for OMV4,  by creating files /lib/systemd/system-sleep/openmediavault and /usr/lib/pm-utils/sleep.d/openmediavault with the code you find in this commit : https://github.com/openmediavault/openmediavault/pull/345/commits/1c162cf69ed00beccdfe65501cb93f6fb1158df0
 
Edit 2:
I fixed the issue related to WoL not being enable at startup. The issue was now that we rely completely on NetworkManager to configure the network interface, the unit file that enabled WoL on eth0 didn't use anymore the right target dependency and was called too early. Just edit /lib/systemd/system/helios4-wol.service,
 
Replace :
Requires=network.target
After=network.target
 
by :
After=network-online.target
Wants=network-online.target
 
then do sudo systemctl daemon-reload and reboot the system