2 titles tags after switching from WPMU SEO plugin to Yoast

Hello team, I have been scratching my head with a double title tags situation.
I was using your SEO plugin then my users prefered the old one as they were used to it. I removed yours, put Yoast as we were used to do. Now, our source on http://www.pupsic.xyz is printing 2 title tags. If I remove Yoast, they still are there. My theme providers is telling me to check with you if your plugin is not inserting something in the database.

Could you please help me?

Current theme: Uplift
Current SEO plugin: Yoast