Yes, according to official statements from Google, keeping expired job postings alive is against their guidelines and can trigger a penalty:
We’ve recently made some changes to our Job Posting guidelines to help improve the job seeker experience.
- Remove expired jobs
- Place structured data on the job’s detail page
- Make sure all job details are present in the job description
If your site violates the Job Posting guidelines (including the guidelines in this blog post), we may take manual action against your site and it may not be eligible for display in the jobs experience on Google Search.” source (Google)