See image for the links being added (it added up to track 3, plus all the works, but not the work-recording links or work-artist links for tracks 4+). As a side note, if it is going to add all the works first, it might make sense to also add the work rels at the same time so that they're not orphaned if something else fails later.

 

Error in console:

 

Uncaught (in promise) Error: Two relationships with the same key
    at r (invariant.js:22:11)
    at u (ReleaseRelationshipEditor.js:441:9)
    at ReleaseRelationshipEditor.js:670:9
    at u (runtime.js:45:40)
    at Generator._invoke (runtime.js:274:22)
    at forEach.e.<computed> [as next] (runtime.js:97:21)
    at r (asyncToGenerator.js:3:20)
    at s (asyncToGenerator.js:25:9)