Cannot modify rule exceptions post upgrade to 9.1.4

Since upgrading from 8.17.10 via 18.19.3 to 9.1.4, we’ve encountered an issue with rule exceptions for users without superuser privileges in that it’s possible to create rule exceptions but once created, it takes superuser access to modify the exception. Having examined the list of individual role privileges, it doesn’t appear to be a specific permission that would enable that either.. Bug or feature?