CDS associations are no longer reflected as native SAP HANA associations (the WITH ASSOCIATIONS clause) in generated tables and views by default, because CAP does not need them and their validation slowed HDI deployments and introduced indirect dependencies between objects. Dated from the first 9.0 release published on npm, 9.0.2.
Native HANA code, a calculation view or an SQLScript procedure, that navigated a CDS association on the database through the native association and expects it to still be there after an upgrade.