packages/acs-kernel/sql/postgresql/upgrade/upgrade-5.10.0d20-5.10.0d21.sql drops the acs_privilege_descendant_map table and related functions/triggers. Then recreates it as a view based on a recursive query.
However...
packages/acs-kernel/sql/postgresql/acs-permissions-create.sql is still creating the table and related functions/triggers.
Also the column names are different between the table and the view--privilege,descendant vs parent,child.
The workaround it to manually run the upgrade-5.10.0d20-5.10.0d21.sql script after creating a new site.
I tried to submit this in the bug tracker, but got an error on submission.