I tried updating my maps today and it seems like somewhere around the threshold of 105k locations I keep running into "Failed to publish map" every single time. File size/location count hasn't changed and I'm seemingly not the only one with this issue, slashp's popular world maps are usually updated daily, and A Pro World and Yellow Belly (~110k) for example haven't been updated since February 5 while IntersectionGuessr (~104k) is fully up to date (last updated February 7), so I'm assuming this is not a me-problem.
Edit: in my case it was a full pano-id map. According to another user it seems like publishing 110k locations without pano-id works fine.