A consortia customer (a member tenant) has reported an issue with z39.50 returning an error - "missing MARC record".

I've narrowed it down to:

When the z39.50 search results for the member tenant contain not shared instances only - the correct results come back.

When the z39.50 search results for the member tenant contains shared instances - the 'missing MARC record' error is returned.

From the inventory UX (looking at a member tenants inventory) - I notice that when the service retrieves a MARC record that is NOT SHARED - it uses the member tenant id.

But when it retrieves a MARC record that IS SHARED - it uses the central tenant ID.

 ...for this specific API call: 

 source-storage/records/341b14a2-1690-597f-879b-6712df7e4423/formatted?idType=INSTANCE

The z39.50 module I believe only works with the tenant id it uses for authentication.  I don't think it has the concept of a central tenantid vs member tenant id.   Is it correct to say that  - if search results for a member tenant contain shared and not shared instances, both the member tenant id and the central tenant id are needed to pull out all of the MARC records (for each of the instances)?  

If that is true - is there any possible workaround?

If yes - it seems like the logic for z39.50 might have to change?