Probably the final update. Jump to the last post as the intermediate posts helped solve the problem, however, the problem was caused by my bad Hubitat misconfiguration (not a coding error as initially expected).
So can somebody please suggest where I can start to debug the following error message? Would you suspect that it is my App code, or a driver/library issue? After further debug (see later logs), this error shows up in the Hubitat log, but it is actually a Konnected.io driver/app issue, that occurs while running a rule machine app (that I wrote) to drive Konnected hardware. This is not an RM issue.
dev:342022-11-21 01:09:18.948 pm errororg.codehaus.groovy.runtime.metaclass.MissingMethodExceptionNoStack: No signature of method: user_driver_konnected_io_Konnected_Switch_580.setStatus() is applicable for argument types: (java.lang.String) values:  (method setStatus)
I am thinking that the only App that interacts with dev:34, K-Z08 HSM Armed SRL (Konnected alarm output that switches on a lamp) is:
Select Trigger Events (ANY will trigger)
HVS-K-Z08 Lamp Test(off) turns on
HSM status reports Armed Home
HSM status reports Armed Away
HSM status reports Armed Night
Select Actions for K-Z08 Armed Lamp ON/HSM Armed OR HVS-K-Z08_v1
On: K-Z08 HSM Armed SRL