When using certain Nintex Forms controls, i.e "People Picker", you may observe the following error:
“There are unresolved entries” 
Although you are using a non-English regional setting, the above error is not being translated.

This is a known behavior and we request users to vote for this change to be implemented via the below link:

https://nintex.uservoice.com/forums/218293-4-nintex-forms-for-office-365/suggestions/31337908-missing-auto-generated-translations