Steps to reproduce:

1. Open Data collection -> Hosts -> Zabbix server -> Discoveries
2. Open Discovery prototypes for any existing LLD rule
3. Create new discovery prototype.
4. Reopen created prototype.
5. See that execute button is available, click the execute now button

Result:
Notification appears:

Cannot execute operation
No permissions to referred object or it does not exist!

See video:

Expected:
There should be no execute now button for a prototype.