As an update, I’ve discovered how to reproduce this issue. I run both Cubase AI and the full version. Since these tracks aren’t supported in AI, if you save a project created in the full version in AI, it alters the project file so that these tracks will never again be visible, even in the full version.
It was pointed out to me by GC that this is stated functionality, i.e. saving projects in a limited version turns off the unsupported features. I’ve asked him to submit an enhancement request to fix this in the next update of AI 7.0x as, stated or otherwise, I feel that altering the project so that the full license version loses functionality amounts to data loss. For people like me who use both systems, it means I’m always one accidental save away from project corruption.
My thinking is that a limited version should limit the funcationality rather than preventing the full version from providing it.
Anyway, since I’ve discovered how to reproduce the problem and also have received feedback on it, i wanted to follow up here for the benefit of any others who might encounter this.
Thanks as always to the SB support folks and their rapid responses.