A DETACHED status typically indicates a temporary state where the appliance is not fully synchronized with the rest of the security group or cluster. Rebooting an appliance can cause it to show as DETACHED temporarily. If an appliance is a member of a security group but currently disconnected, it can also show as DETACHED. An issue with the downlink cable can disrupt communication and cause a DETACHED status. However, the version of the appliance, such as being installed with R80.20, does not inherently cause a DETACHED status. Therefore, the correct option is that an appliance installed with R80.20 cannot be a reason for the DETACHED status.