[WordPress SEO Plugin] Google pulling up wrong titles all of a sudden

We recently revamped our entire site, which included changes to a lot of pages, as well as additions. During the process, we also changed a lot of the SEO titles. While the new theme was being built, we had it on a completely different domain. While it was there, it had the wrong site title (missing an “S”). We fixed it, transferred the theme & database to the correct domain, checked everything in Google, monitor it regularly, no problems.

Now, all of a sudden, some of our pages are missing SEO information altogether, pages that had complete SEO titles, keywords, etc. The Site Title also reverted back to the wrong one (missing the “S”). We have not made any changes in regards to theme files or plugins. Simply adding and editing pages. We have not even looked at the Settings page. Even though the homepage has the Yoast plugin info filled out correctly, Google results show the wrong site title, rather than the current SEO title for that page. This seems to be a random occurrence in Google, because some pages have the right titles and some do not.

Why would these titles stop working all of a sudden?