The third floor person is correct, as is G&S. To remove the wave the floor needs to be sanded over. It should be sanded on a slight diagonal angle first, to remove the waves. After going through all the grits, the floor can be sanded with a buffer or something like a Trio machine, then screened and finished. The person who did the job should make it right, but they need to inspect the big machine used on your job.

https://homeguides.sfgate.com/avoiding-chatter-marks-wood-floors-32653.html

This happened to me when i hired a company to redo my hardwood floors. It took them DAYS of sanding and it’s still noticeable waves. And the guy denied any wrong doing. He told me this Is the last time I can ever have my floors refinished. It’s also the FIRST time these hardwood floors have ever been refinished. He destroyed my floors by doing this and then way over sanding to try to fix it. And there's nothing I can do.

"A picture is worth a thousand words."

Every flooring contractor these days have an online portfolio that includes photos. Everyone should carefully examine it, before hiring. Reviews are great, but should be backed up with quality photos. The photos will tell you how good the contractor really is.

Do not just look at the photos - look in the photos. You can examine online photos by zooming in and out into different parts of the photos. Defects such as sanding lines, swirls, waves, chatters, dish outs and blotches will show through in the images.

It will help you make a better "financial" decision in hiring. Avoid bad "financial" experiences. Decide which contractor is the best value to make sure that your "financial" expectations are met.

Any chance you can get a different local extremely reputable wood floor pro to look at it in person? Maybe even pay them a consultation fee....Obviously, you are hoping to avoid what Erin went through (so sorry Erin :(. It would be wise to get good on site advise before they attempt a fix as yes (good advise above) you may need to rethink who exactly does the fix.

Thank you all for your insight and guidance. In the end, we paid out of pocket for an inspector certified by the National Wood Flooring Association (NWFA) to evaluate the floors. He concluded that the floors do not meet acceptable standards.

i know this is an old post, but can i ask what you ended up doing with the floors? did you keep them as is? re-sand them? Thanks!