I messed with some things this morning, and then at noon I got status reports on my new phone and this afternoon got a picture while the phone was sitting idle, so looks like the issue might be fixed.
I looked at different things, but the difference might be that I went to:
Settings => App Settings - Installed Apps => Spartan => Battery saver
... and changed it from "Battery saver (recommended)" to "No restrictions".
Another thing I did was unlock Android developer options so I can look at running services. Spartan was listed as a cached process before I made any changes, and this has not changed.