Version is 1.12.6. I tried going to the Device page, but even there I can't edit that field because there's nothing to click on, there is no "-".
This was a bug that was fixed in a later version. Suggest you update to to 1.12.10.
Are you using 1.12.10?
You should be able to go to http://SERVER/open-audit/index.php/devices/ID
Where ID is the device id of the device in question.
If you're looking at a Bootstrap-themed page (in the latest release) you should see a - where the name should be. On the pages that are Tango themed, no guarantees.
I have multiple Cisco devices found during a SNMP scan that don't have hostname and I can't edit it for the device because there's nothing to click on, no name and no '-'. I have tried re-scanning and SNMP scanning the device, but no change.