I made a test for this issue - The Jerusalem Post. I edited this issue, I added new meta title, meta keywords and meta description and every time I can see in front-end, source page, all my changes. Please let me know if this issue persist and how can I replicate this.
1. I edited "Israel" Publication, I set "Israel News" meta title, keywords and description
2. I saved this publication
3. I edited "USA" publication and I added "USA News" for meta title, keywords and description
4. I saved this publication
5. I edited again "Israel" publication and I can see "Israel News" for meta title, keywords and description