Two Title Tags in Head

Since upgrading to AIOSEO 4.x I see two title tags in the head of all of my sites. One of these is from my theme, but before the upgrade to 4.x I believe the plugin would replace the title tag from the theme with one generated by the plugin. Now it seems that AISEO adds a new title tag but leaves the theme-based title tag in place as well. I’ve looked for settings to change this behavior but can’t find any. I can of course remove the title tags manually from all my theme heads, but I’d vastly prefer that the plugin reverted to its previous behavior of ensuring that only one title tag exists in the markup. Thoughts?