Newly finished white oak floor (installed/finished May 2018 with Bona Intense seal and Bona Naturale) developed these small dark circular stains 1-1.5" in diameter. Originally thought it was from the rubber feet of an air compressor vibrating and polishing/discoloring the floor, then thought mouse pee, but urine stain remover, CLR, acetone, baking soda, bona cleaner, or a light sanding do not remove the stain. Any ideas what it could be? Last idea was the finisher guy was sweating and applying finish over a drop of sweat soaked into wood. No idea what it is....
https://ibb.co/X3MqZqw

This looks like a stain that has penetrated through the finish which can occur before the finish has cured. It is from contact with a circular machine base, most likely rubber that had a liquid under it. My air compressor has the same type of rubber feet under it. It is probably a stain in the oak surface that will need to be scraped out to remove them from under the finish.