Were the floors fully sanded to bare wood? Sealers need to go over bare wood, no finish. If, over stain, the stain needs to be completely dried .

Yes, fully sanded to bare wood. We then bleached the red out with the Part A/B solution. 36 hours later is when the Bona NaturalSeal was applied.

The red out leaves a chalky residue. that needs to be washed off or buffed out. That is most likely your bond breaker.

Red flag , if, your contractor does not know the cause and fix.

I'm going to disagree with G&S on this one and I have lots of experience bleaching floors. We rarely buffed floors after bleaching.

This is a very odd problem so I hesitate to cast doubt on the skills of your contractor.

The only time we had an unusual issue with any waterborne sealer or finish involved a house with high humidity and no hvac or ventilation. Other culprits could be old or improperly stored finish, moisture in the floor, mixing water in the product, uncured bleach, improperly mixed bleach or ?????

How is the adhesion on the balance of the floor? If it's okay, looking into why only certain areas are affected, could shed light on the cause. Is there a/c? Is there a thermo-hygrometer in the area? What's the moisture level in the wood? Is it different where adhesion failed? Was the bleach neutralized with vinegar? Was it only one coat of NaturalSeal? What was the final sanding grit (it shouldn't matter since the bleach pops the grain and should help with adhesion)?

It won't take much to sand this off. I'd monitor RH and temp, neutralize the bleach with white vinegar, and do a separate room before the entirety. Do make sure the floor is extra clean before bleaching. Check your finish application rates.

I would not move forward before inquiring with Bona tech support or their regional rep.

Thought this was Bona red out on the floor. If, it is regular bleach. It needs to be neutralized with borax.