Random error popping up in Search Center

Hey everyone,

 I joined this org earlier this year and am getting around to building a custom search center, the site was a lift and shift from SP2010 to SPO prior to my starting here, and as a part of that, there a lot of random things I need to clean-up. This error pops up on the search results page, but I can't tell where it's coming from or what triggers it. It appears after mousing-over a result, as shown in the screenshot below. I've tried fiddler and Chrome dev tools to determine where this is coming from, but no luck yet. After clicking Ok, I do get the normal search results and no longer receive an error message for any of the results on this page.

Thanks,

Eric