In this announcement, Google have referenced the new guidelines which can be read here. The new guidelines cover several key considerations:
Expired Job Removal
Google don’t want their new enhanced search experience to be clogged up with useless, unavailable roles. This is a real risk; use of the Job Search Engine would be quickly impacted if users were constantly finding their time wasted by being directed to expired jobs. This is no doubt why the punishment could be harsh (a manual ban from the platform). You can find out how to remove postings here: https://developers.google.com/search/docs/data-types/job-posting#remove-job-postings
Correct page Schema tagging
Often, developers will tag the wrong pages with schema data, meaning Google is getting the wrong or duplicate information. For example, tagging all of the listings on a category page. Google want the single, most detailed page for each job to be tagged with Schema (so, the actual job landing page only).
Correct Salary Information
Google have said that if salary information is being added to the schema, then it should also be shown on the job landing page. So as normal practice for SEO, no showing Google one thing and your users another!