SAP DBTech JDBC: [258]: insufficient privilege ... again!

I have found plenty of threads on the subject of "SAP DBTech JDBC: [258]: insufficient privilege", but nothing that seems to be helpful for my situation

The following statement on compposite provider 'COM_PROV_XYZ': 

select * from "_SYS_BIC"."system-local.bw.bw2hana/COM_PROV_XYZ";

fails with the message: 

Could not execute 'select * from "_SYS_BIC"."system-local.bw.bw2hana/COM_PROV_XYZ"'

SAP DBTech JDBC: [258]: insufficient privilege

The following select on calc view 'YYY' works though:

select * from "_SYS_BIC"."ProjectX/YYY"

Which agrees with the fact that the user has been granted roles with the followin auths:

(also the case for _SYS_BIC and _SYS_REPO)

Also:

Any ideas out there?