Plugin causing alignment issues in template

Wasn’t able to get this plugin to work with my theme, so I disactivated and it caused all sorts of alignment and formatting issues on the pages. I reactivated and it went back to normal. Plugin was added months after site was started. Tried uninstalling and have same issue with the layout going crazy.

PLEASE, I hope there is an easy fix for this. I haven’t added any other plugins since this one, or for several weeks prior. Client wants to go live this week. And I don’t want to risk running another site map plugin and have this one active. Right?

https://wordpress.org/plugins/sitetree/