Regarding the JobMonster pages, last night, we fixed these issues of Blank pages, Header Title in other Languages, ...
Simple tutorial to set JobMonster pages with WPML :
a) JobMonster pages (Home, Jobs, Resumes, ...) need the URL slug in English for all languages
Step 1, edit your default English page (Pages/All Pages) and switch off the WPML's Translation Editor
Step 2, Duplicate or edit the pages in other languages, set the URL slug in English for all languages
Example with "Jobs" page and mandatory "jobs" for URL slug
English : https://www.sitename.com/jobs/
Spanish : https://www.sitename.com/jobs/?lang=es
b) For other pages, it doesn't matter (Contact Us, About Us, ...) and the URL slug in other languages could be translated (It might be WP standard page and not JobMonster page but we cannot confirm it because we don't know)
Example with "Contact Us" page, the URL slug can be translatable to any languages, it doesn't matter :
English : https://www.sitename.com/contact-us/
Spanish : https://www.sitename.com/contactenos/?lang=es