I think the point Jordi is trying to get across, is that there is an issue with the field mapping between Open Archives and FamilySearch.
If we look at the record in OpenArchives you'll see that the field for spouse is called (ex-)partner, because that's what the field is called at the primary data source, the Gelders Archief:
this results in the partner not being mapped in FamilySearch, as you can see here:
if you then go to Tools > Review Attachments in FamilySearch, the partner's name doesn't show as per the screenshot Jordi provided
Let me provide a second example, here you see that the record in Open Archives has a field for wife, and a field for Widower (or better widower of):
again this is based on the data OpenArchives receives from the primary data source:
if we look at this record in Family Search, you'll see that wife has mapped to Spouse's Name, and this information can be attached to a family tree in FamilySearch, but the information of the former spouse of the deceased was not mapped at all
in short, in the system integration design the field mapping has been done incompletely - for whatever reason -, and as a result FamilySearch doesn't contain the same information as OpenArchives