I’m having a similar issue with the Yoast SEO plugin except it’s not just the SEO Title that’s disappearing. All of my WordPress SEO fields are disappearing. It appears that the entries are indeed being saved initially because I’m able to find them in the database after I edit my SEO Plugin fields for a post.
The problem is that the next time I edit that post, the fields come up blank so if I save my edits, it blanks out whatever was saved into the database the first time. This is a problem with retrieval of the previously saved entries.
What makes this even more bewildering is that I’ve got this installed on three different environments and it works in two of them, but not one of them. The one that it fails on is unfortunately the one that matters the most. The difference that jumps out at me the most between the three servers is that two of them are running PHP 5.2.17 and the one that’s not working properly is running 5.2.6 with the suhosin hardened PHP module enabled.
I’m using WordPress 3.2.1 and the 1.1.2 version of the plugin. I apologize for not being able to provide any more helpful details. I’m hoping that someone else ran into this same issue and can tell me what they did in their case to resolve the problem.