In the Spectrum Control Panel, information messages showing the following are seen:
Queueing stale model <modelhandle> of name of type RTM_TestHost for destruction.
This messages can be taken care of by updating the following $SPECROOT/SS/.vnmrc entry:
Update it to yes so it will activate SPM test hosts after activating all other device models.
The .vnmrc file is read when the SpectroSERVER is started, so a SpectroSERVER restart is required.