Power Users seems to no longer be able to add Network Interfaces to Virtual Machines.
Super Users of course have no issues. The power users have been granted NetworkUser Role on the respective Networks, PowerUserRole on the respective Clusters/Storage Domains.
This failure mode is with the currently running ovirt-engine I built from commit: 899d96c055784a54b6d2b8181e5ed13b258d009f
This used to work with my previous engine build from commit: 82bdc46dfdb46b000f67f0cd4e51fc39665bf13b