Precondition:
Master only (7.0.0alpha2)

Steps to reproduce:

• Create a discovery rule with e.g two unique SNMPv1 checks:
  -) Port range for both checks ->161
  -) SNMP community for both checks -> public
  -) SNMP OID for first check -> iso.3.6.1.2.1.1.4.0; for second check ->iso.3.6.1.2.1.1.5.0
• Open newly created discovery rule
• Edit any SNMPv1 check
• Press the update button

Result: Validation error 'Check already exists.' appears. The same problem appears with updating SNMPv2 and SNMPv3 checks.

Please see the video attachment:

Expected: no validation error should appear because checks are unique in this case.