Can't swap between MHC assets from Quixel Bridge and MHC assets from the marketplace

Hello, I have a project containing some metahuman assets that I’ve downloaded from Quixel Bridge, and some that I’ve downloaded and migrated in from a different project, that originally came from the marketplace. I want to end up with a situation where I can swap all the different heads between one body. At the moment, I can swap the Bridge heads with each other, and I can swap the Marketplace heads with each other (either via blueprints, or in the skeleton/mesh windows (that have skeleton/mesh/animation in the top right corner, and where the retargeting manager is). However, I can’t swap the marketplace heads with the Bridge heads.

I’ve looked at the skeleton for both types, and they both look like they have the same bones but with different vertices weighted again them. The Bridge version uses a bunch of bones labelled “12IPV”, and the Marketplace version uses everything aside from those “12IPV” bones.

I’m wondering whether I need to re-target the skeletons, or whether there’s a setting somewhere to decide whether to use the “12IPV” bones. When I’m retargetting body animations, I retarget everything to “humanoid rig”, and match poses so that I can transfer animations, but I can’t find an equivalent for these heads.