Hi all!
I’m looking for some guidance on pre-finished Johnson solid hardwood flooring. It was installed about 20 years ago, and we are in the process of refinishing. I’m not sure of the wood species, possibly Brazilian oak or American oak??

We are running into unexpected yellowing issues during stain/finish testing, and our flooring contractor is at a loss — just keeps saying “it must be the wood!"

Here’s what’s happening:

• The floors have been professionally sanded to bare wood (starting with 40 grit), but we’re seeing bright greenish-yellow discoloration appear within 12–24 hours after applying light colored stains (e.g. DuraSeal 50/50 Country White + Neutral with 1 coat of oil poly finish OR 2 coats Bona NordicSeal + 1 coat Traffic HD.)
• It’s not consistent from board to board, but it’s happening regardless of whether we use oil based or water based products. Of course there is natural variation in the wood but this is really a strange yellow color that appears hours after application. It’s not the normal dark/light variation I would expect to see. And there is often a faint yellow cast that develops overall.
• I’ve scoured the internet and can’t find anything like it. It doesn’t resemble typical tannin bleed (which I understand usually appears as brown streaks or patches). This is more of a neon yellow hue, and it’s appearing in otherwise clean-looking boards.
• We wonder if this may be due to residuals from the original factory pre-finish (possibly embedded sealers or oils) that are chemically reacting with water-based sealers or light-toned finishes. Is that possible??
• Any other ideas??

Ideally we're trying to achieve a light whitewashed finish. Also open to a natural wood finish, but want to avoid strong amber tones that were originally present.

What I'm wondering is:

• Has anyone seen this specific type of yellowing issue before??
• Is there a product or best practice that can help mitigate these reactions?
• Do we need to give up on lighter floor color and go with darker stains to help disguise the issue while staying away from the old orange tone? (Note: I even see a little of the neon yellow in darker stains that were tested, but it’s less obvious of course.)

We're mid-process and getting desperate, so any input would be hugely appreciated. Thanks so much in advance!