WordPress SEO by Yoast is a great SEO plugin for WordPress. It allows you to tweak your WordPress site so that it’ll be SEO-optimised. One odd thing that happened to me was that after I updated my post titles, it didn’t seem to change the actual title in the <title> tags when I visited the page. Viewing the source of the page showed that my title was there, but only in the <meta property=’og:title’> tag.
Long story short, I found that all that it took was to go to your Yoast WordPress SEO settings >> Titles and Meta, and then check/uncheck “Force Rewrite Titles”. Even though it said that the auto-detection would take care of this setting, I found that I needed to manually check it to get my site titles to work.