I’ve edited and exported a SubMachine MOGRT but when I run Create Subs nothing’s changed.

When you edit a MOGRT it is vital you rename the MOGRT. SubMachine searches the Motion Graphics Template bin in Premiere Pro by name so if you haven’t renamed your new MOGRT the old MOGRT may be found first and used by SubMachine. Renaming your MOGRT solves this issue. You can also delete some or all of the old MOGRTs from the Motion Graphics Templates bin.