The "connection lost" issue at https://discourse.nodered.org/t/node-red-connection-lost/1724 does not apply to my situation. I'm using node (v11.6.0) and npm (6.5.0-next.0) and stretch will all updates/upgrades applied on RPi3.
Both PiSense HAT nodes (in and out) display "disconnected" status message after "some" random period. Node-RED is running as a service per official documentation. Other related nodes, Wunderground, Inject (fixed periodicity) and others, are working fine per my understanding. Even if I close the browser, PiSense HAT nodes stop transmitting/receiving (per respective node) after a while.
I am probably making a basic mistake. It is very elementary linear PiSense HAT flow. What should I look for in the logs?
P.S. Getting back to Node-RED after an year's absence and it shows! Still need to fix the Twitter node at my end.