Half of my 31,000 images are geo-tagged incorrectly

Help!

I am trying to convert to an iOS-only workflow, migrating from Lightroom. However, in OS X High Sierra, I have moved my 31,000 images from Lightroom to Photos, and almost all is well. However, I just noticed that in Photos, roughly half my images are geo-tagged as "Northwestern School of Law" in nearby Portland Oregon. I have tried everything I can to either remove that tag or revert to original geotag data.

For me, selecting all images and trying to select "Revert to Original Location" goes through the motions of doing something, but does not actually fix the 14,742 images tagged "Northwestern School of Law".

Furthermore, this location and problem, does (did) not exist in Lightroom. Most of images aren't actually geo-tagged, at least, not by my camera, so I'm not even sure how this happened in the first place. If anything, my goal is to have all images that weren't geo-tagged by a camera, to have no geo-location data.

What can I do to fix this problem!?