Editing an instance field not controlled by MARC, in some Source = MARC instances, returns a 422 (Juniper bugfix)

Overview:

I was looking at records with preceding/succeeding titles and found I could not give them statistical codes. This happens on both bugfest and ref envs,.

Steps to Reproduce:

1. Log into folio-snapshot-load
2. Import a record with a preceding and/or succeeding title like Good Housekeeping 2497043 (sample MARC file with several titles attached), using the Inventory Single Record Import or Default Data Import job profile for creating SRS MARC Bibs and Instances
3. Go to Inventory and find one of the newly-imported records
4. Edit the instance, and attempt to edit any of the instance fields that are not controlled by the underlying SRS MARC (the 3 checkboxes at top, Catalog date, Instance status, Statistical code) and save it

Expected Results: The Inventory edit is saved (since these Instance fields are not controlled by the underlying SRS MARC Bib)

Actual Results: You can't save the record, console shows a 422 :

{ message: "Instance is controlled by MARC record, these fields are blocked and can not be updated...}

<- abreaux - similar is also happening in https://folio-snapshot-load.dev.folio.org/inventory/edit/5fb72380-c2d8-4d08-a8b3-6185674586bc/instance?sort=title&xidtype=f26df83c-aa25-40b6-876e-96852c3d4fd4 – which I (Charlotte) just tested

Additional Information:
Might be related to the bug report: MODINV-429 ??
URL:
Interested parties: abreaux