I create a field called MyData in Computer group and then follow the steps below
2. edit the newly created field, say set MyData to 111
4. Go to other page
5. Go to http://localhost/open-audit/index.php/devices/1 again
I find that it will show 2 MyData fields. One of them is 111 and the other is empty.
I just repeated your steps on a Windows install of 1.12.10. It worked as it should (ie, no duplicate field).
Can you tell me what OS your Open-AudIT is installed on? What version of Open-AudIT is it?