Have tried Goom and Shader from Libreelec repository with same result, so I don't think it is the visualisation. Also problem exists on the last two stable releases of LE.
Just noticed that the next release of Kodi 19.X shows the following additional functionality.
- New setting to open music fullscreen/visualisation window automatically when playback is started
So while it currently starts under Kodi after a short delay and can be manually started looks like they are adding an option to commence immediately. Perhaps the problem does exist in LE and can be fixed with the next release. Any thoughts from the Devs.