Alternate Version Arcade Games Refusing to Import using MAME Metadata

[Abaddon]

Hi there, I'm trying to import a romset for Final Burn Neo that are using MAME naming structure. If I import without Force using MAME metadata, huge chunks of the roms don't connect with the metadata. If I select the use MAME metadata option, this works fine, but I'm finding a number of alternate versions of games are refusing to import correctly. I'm using "Force Importing Duplicate Games" and "Combine roms with matching titles into a single game" in the Custom Options, and "Import all clones" in the MAME metadata options, seen below for the settings used:

An example of the issue is Teenage Mutant Ninja/Hero Turtles. All the roms varients are showing in the Ready to Import window listing versions under 2 games - TMNT and TMHT, but when I go to the list of games it's only showing TMHT, not TMNT and nothing is showing under the Additional Apps, example below:

There's definitely something dodgy going on though, as I've found games with missing versions that show a "Play Version" option, but only a single entry listed under it, the same in the Edit game window. Can see below Battle Chopper and Mr Heli showing as separate games, but once in LB, searching for Battle Chopper only shows Mr Heli, but it has a Play Version as if it believes there's more than 1 available:

 

The only way I can get it to import the roms correctly is to not use Combine Roms, which then pulls through all the games expected but then I end up with everything expanded and I'd have to manually combine every game's version in the library.

Edited January 25 by Abaddon