Not sure if this is you or them but we have a problem with the formatting of the following plugin which don’t occur with the 2015 theme with the base required plugins for Kleo installed. Essentially it acts as a glossary which highlights text and delivers a popup on hover with more information and a link to a page in the glossary. On the latest Kleo however in Chrome the hover jumps the user to the top of the page and in MSEdge it white’s out the page. I am not sure where the issue lies and wonder if you can help. I can grant back-office access and I have also attached it  so you can try it on your own installation.
If it is not your problem please come back to me and I will try the vendor or simply not use it, but that would be a shame because it adds greatly to the functionality of the site.
We currently have it disabled but I can reactivate and give you back office access if you want to see the problem at work.
Best wishes