I was having problems with a new install of WordPress Seo by Yoast. After entering the Focus Keyword and other details for a given post and clicking Update the fields would empty themselves and be unrecognised on the Page Analysis page. They are, however, recorded on the main Pages -> All Pages page in a column.
I disabled my other plugins and that fixed the problem. Everything works fine, great in fact. The offending other plugin turned out to be Related -
Can these be made to get along or should I start looking for a new plugin?