Error: "Aii, non-unique meld keys"

[doughnet]

Aborting due to error: Aii, non-unique meld keys: {
"Chrome-mesh",
"Default 150:150:150-mesh",
}

For my testing (first time using this varientMeld) I have 6 different .glb files of the same model/object. Each has a different metal finish (chrome, brush nickel, matte black, satin brass, polish brass & oil rub bronze).

Command:
dist/app.js sb:3d/BCU4-SB.glb mbl:3d/BCU4-MBL.glb ch:3d/BCU4-CH.glb bn:3d/BCU4-BN.glb br:3d/BCU4-BR.glb orb:3d/BCU4-ORB.glb

Parsing source asset: '3d/BCU4-SB.glb'...
Aborting due to error: Aii, non-unique meld keys: {
    "Chrome-mesh",
    "Default 150:150:150-mesh",
}

All the files were exported from the same model in KeyShot (only changed the material/finish). I also tried making individual files of each material/finish, saving it and exporting it but that didn't work either.

Is there a step I am missing?