Here’s the patch work done

It's a natural shake or split in the wood. If, it is thin enough, when it comes in contact with water or water base finishes. It will bubble and curl. It's hard to detect during installation when floor boards are still dry and in it's free state.

Is this how you would have fixed it?

Filling it with putty or wax sticks after it has been stained and fifinish . is the best way to address it without having to redo the entire project.

For the best look is to replace the floor board. but, that can invovle redoing the entire project if the stain does not match.

You know what you have now for a overall end result. The filling can be worked on more for improvement.

Or you can gamble and do a board replacement. Your stain nay not match. You can have a blotch in the floor. Then you will need to decide whether you want to redo the entire project. The result maybe different.

Assuming you were willing to pay the significant added cost, the ideal solution is to cut out and replace the offending board, carefully matcing the wood and any stain. Doable, but neither particularly easy to do well or cheap. They probably should have offered you a choice.

Thank you so much! I spent a lot of money getting these darn floors done and I want to make sure we are getting good quality work and I needed to hear that from a professional. I can tend to be overly critical and I didn’t want to be a pain in the butt when addressing it. I don’t think I want them doing the entire project it was a big one and that floor is about about 16 yrs old. I also got some carpet pulled up and replaced with oak floors that’s section is a little lighter than the rest but I expected that.

As G&S accurately points out, this is a natural split or shake. The problem with these is that they usually become apparent during or after the finishing process, when removing and replacing a piece would often look worse than the defect. The repair done looks decent.

Thank you all for responding!!

Frankly, not a very artistic repair. If they had a little more skill it could have been better. FYI, I purchased a new dresser. It had a penny sized dent it the top center edge, couldn't miss it. I accepted delivery with the note if the damage. They offered a big discount and offer to repair dent, if repair acceptable, or refund/return if I didn't like repair. They sent a furniture repair guy fixed it so we'll, 30 years later it's still good.

Maybe a furniture repair person can fix that better. If it's not in a prominent area not noticable maybe just leave it.