Fully updated F27, Dell XPS 15 9550.

So last year on F26 I could safely and reliably suspend to ram from the menu, then after the upgrade to F27 all that stopped. I just dealt with it until last night.
So Google let em down again with the VAST majority.. if not damned near all of the results centered around Hibernation.  It seems as if Suspending to ram just magically works for most people.

So I know that using the menu (KDE Plasma) Suspend to Ram in all fairness just shuts down.

Now testing last night I could 'sudo systemctl suspend' and it worked.  First tkme for a minute, second time for 10 and the third overnight.

Fast-forward to this evening, I ran 'sudo systemctl suspend' upon  leaving the office. Get home and about an hour later I open the lid and it's shut down and rebooted yet again.

So my question is, where are the most effective places (logs, config files) to look to troubleshoot WTF is happening?
Thanks!