WordPress SEO was updated to version 1.5.5.3, from version 1.5.5.2. Changelogs:
1.5.5.3
- Prevent dying on edit post page for new posts / pages without focus keyword.
- Fix replacement of %%excerpt%% in snippet preview.
1.5.5.2
- Fix wrong SEO Analysis value icon, regression from 1.5.5.1
- Add role specific removal from XML Author sitemap
- Add option to exclude user from XML Author sitemap on user profile page