Can you please, attach the screenshots of the rules?

Thanks for the reply! Here is the rule I have for Read Only on the lookup dropdown field:

not(contains(parseLookup([Form].[ASSIGNEES 1]),[Context].[Current user display name]))

Essentially, if the current user is not listed in the person field (ASSIGNEES 1), then disable the dropdown field. Again, the actual enabling/disabling part of the rule works. But when the field is enabled, the options in the dropdown do not show. It just says "No Options". So weird!

The intent behind this is that I have multiple people using the same form and I only want them to be able to edit the things that are assigned to them. I've also tried creating a workflow variable that parses the ASSIGNEE field before hand and I get similar results. 

I completely rebuilt the form from scratch and I get the same results. I'm assuming this may be a bug with Nintex. 

My workaround was to create a hidden Text - Short field. Then I created a rule that says "if the user is not in the assignee field, set the Text - Short field to be the value showing in the lookup dropdown and set it to read only." At the same time I'm hiding the lookup dropdown and showing the text field. Essentially, instead of setting the lookup dropdown to read-only, I am instead hiding it and showing a read only text field that duplicates the value selected in the dropdown.

If I change the dropdown to be radio buttons, the values load just fine. But for some reason lookup dropdowns won't load values if there is a Read-Only rule attached to it. In my case, specifically a rule checking the current user to a person field.

Any idea where I can submit bug reports for Nintex?

You can send email to support@nintex.com for bugs

Great, thank you!