Steps to reproduce:

Everything was working fine up to version 7.4.5; the issue began in 7.4.6. The "Group prototype" fields now flag an error, claiming that a discovery macro is required—even though one is already present.
I have just set up both version 7.4.16 and version 8.0.0rc2, and the problem persists.

Steps to reproduce:

1. Go to Data collection > Hosts > Discovery rules (Host prototypes).

Result:

Expected: Re-enable the creation of groups, as is standard in version 7.4.5