Nintex form(s) with rules no longer fire

We have quite a few Nintex 2013 forms and workflows which were working fine for few years until today morning. Few issues listed below:

1. On some forms, the list item attachment control is not loading/visible on the form (the attach control is visible in the ribbon but not doing anything when clicked)
2. On some forms rules are not working that would show/hide controls based on a dropdown change or checkbox checked/unchecked. The hidden controls are not loading on the forms and these fields have conditional validation rules too (mandatory if applicable/visible).
3. On some forms change of dropdown should auto populate certain controls

We have confirmed with the networking team that no browser policy was changed, and no security/windows patches were applied.

Please help. All our production forms are broken.