Field Required Error with Behaviours

A field required error of a security level field that is configured in a field configuration occures even though it is filled.

Steps to reproduce it:

1. Add security level scheme and set one of the security level as default.
2. Associate the security level scheme to the project.
3. Configure security level required via field configuration.
4. Configure Behaviour and add the script below in the Initialiser:

   if(getActionName() == "Create")
   {
      def field = getFieldById("security")
      field.setReadOnly(true)
   }
   

5. Add security level field into the create issue screen.
6. Try create issue without putting Summary value to force the error out. And then, fill in the summary value then click submit. However, error prompt saying security level field is required even though there is a value on it.

Notes

This is happening to another field when a required field is not filled in.