I have a survey where I'm using a Repeat to edit data in a related table in addition to a point feature service. I've created the relationship class using GlobalID on the point layer and parentGlobalID (a GUID field) on the related table. Everything is working except that when I submit a survey, there is an extra, totally new, GlobalID value that gets populated in a field that should be a text field (called "Project Number"), in addition to the correct parentGlobalID that references the main point, and the related table record's own GlobalID. The submission_URL points to the main feature service, not the related table.
Why is this happening?
Relationship Class (created in Pro, published to AGOL)

Survey123 form

Results in related table:
