"Add Options" widget does not work for all users

Hello, we have been using the Add Options widget for some time but recently, some users are having trouble with it.  The field to add new items does not show up and the + button does not work. 

This is the way it should look. 

but this is the way it actually looks on their computer.

I did test the form and I was not able to replicate the issue. The add button is working properly on my end. Here's a quick screen capture of my test:

Please try using a different internet browser and see if the issue still persists. You can also use my demo form to test it further: https://form.jotform.com/80385191924966

You can also check the User Contributed Checkbox widget. Here's the link: https://widgets.jotform.com/widget/user_contributed_checkbox