Found issue...
Song was using v9 VST3 version.
For some reason with v10 the VST3 version of IM Pusher was not in Cakewalk VST database (registry)
Tried reinstalling Waves IM Pusher - no change.
Had to run a reset on VST database then after rescanning it showed up and v10 version now loads up in the song with it's former settings.