It doesn’t help @Scribe2, but I experienced a similar issue with the manjaro-gnome-26.1.0-260812-linux71.iso installed onto a VM. I flagged the issue in the release thread.
From experience with ThinkPads, ThinkCentres, and ThinkStations, if secure-boot remains activated, the Manjaro image doesn’t boot at all, so it’s not even possible to reach the installer, which is expected. @Scribe2 should be able to confirm if he disabled secure boot for his IdeaCentre, but yes, sounds like he’s not coming back.