Maybe you could install from another drive, boot High Sierra, open Mojave installer, then point the installer to the drive you want to install.No, never have on this Mac and I used disk utility immediately prior to trying to install the OS. Erased drive and tried both APFS and HFS+. No go! WTH.
Only one drive in system, a 512GB SSUAX.
It's a 2009 5,1 cMP, with 138.0.0.0.0.