MARC field protection is overly strict in our current Folio release, Lotus Hotfix 1.
In general, if a target record being overlaid contains a protected field, any other protected field in the incoming record will be rejected (e.g. if target records contains a 590 and incoming record contains a 866, the 866 will be rejected).
Rejected fields from incoming records have to be manually added via Quickmarc.
Current protected fields include: 590, 866, 867, 868 and 907 (which contains our legacy Sierra .b numbers)
This behavior is supposed to be improved with Lotus Hotfix 3 (hopefully September), and then improved even more with Morning Glory (hopefully October).
Main takeaway: every time you overlay a record, make sure that all the fields you want to see in the record are in fact there. If they’re not, add the missing fields in Quickmarc.

866, 867, 868 holdings statements

Holdings statements for multipart monographs will ideally be contained and surfaced in the “holdings statement” element of the Folio holdings record. Existing multipart mono holdings statements (all bib-level 86Xs) were migrated there.
However, EDS is not able to display the “holdings statement” element from the Folio holdings record for monographs, at least not right now.
Workaround: continuing to populate and maintain 86X in bib record and have EDS surface these fields as “notes” in the detailed display.
Job profiles CAT1 and CAT2 have a mapping to create “holdings statements” in the Folio holdings record from 86Xs in incoming bib records (but field protections are an impediment to this working correctly for overlays)
For now, holdings statements for multipart monos need to be maintained in both the bib and the holdings record.

Review of current Folio job profiles for cataloging

Job profiles with prefix CAT are those for use with the Data Import app
Job profiles with prefix TARGET are for use with Single Record Import in the Inventory app

Job profile name	Job profile behavior
CAT1	For new records to the system; no overlays Creates new MARC SRS record and Instance Creates a Holdings populated by values from 948 Creates an Item populated by values from 949
CAT2	For overlays; matches on Instance HRID from 947 $c Creates or updates MARC SRS record Instance is updated indirectly via the changes to SRS Creates a Holdings populated by values from 948 Creates an Item populated by values from 949
CAT3	Same as CAT1, but for serials (i.e. new records)
CAT4	Same as CAT2, but for serials (i.e. overlays)
CAT5	For overlays to update only the MARC SRS and Instance Only operative 9XX is 947, with $c as the Instance HRID matchpoint

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