GLTF -import only animations - not working with existing skeleton, but works fine after reasigning skeletal mesh

version 5.4.2

I have an existing skeleton I want to import animations for, but for whatever reason the interchange throws

SkeletalMesh does not exist, the skeleton and skeletal mesh is obligatory to import this animsequence

When I import the asset as a whole creating a new skeletal mesh, the animation sequences are created properly. When I delete the knewly created skeletal mesh and double click the animation sequences UE asks me to reassign the skeletal mesh for those sequences. When I select my target skeletal mesh the sequences work perfectly fine.

Another weird thing is after reasigning the skeletal mesh and I import the same animations ( not re-import, just import ) and use the import only animations option then it seems to work fine. But not before.