Ok so 5 months ago (june) i ripped out the tile in my kitchen and dining room and got a professional hardwood floor company to feather in new #1 red select oak into my 30 year oak that was in my living room and 3 bedrooms. He installed, sanded, stained, sealed and put 3 coats of oil based poly (satin finish). Results were PERFECT!!! Now 5 months later in alot of areas the poly is starting to peel along some seems were the boards meet each other. I called him right away and he came by to look at it. He said because of the temperture differences in the seasons (summer to winter) it will sometimes happen and to only fix is to remove all my furniture out of my house "again" and theyll come in, light sand and put another coat of poly. Now my questions are.

Is that the real reason this happened?
Is this the correct way to fix this problem?

ehh, There are a few ways to have a bonding failure. 1.Lack if proper abrasion between coats. 2. Stain not dry before finishing 3. contaminates like wax or pledge. All three are his responsibility normally, did he stain and finish in the same day? Either way he is standing behind his work so id go with the flow and let him fix his mistake.

Thanks for the reply Kev. He stained 1 day, came back a couple of days later to seal and put 1st coat of poly, came back 2 days later for 2nd coat of poly, then 2 days later for the 3rd coat of poly. He is def standing by his work by going to try and fix it but my question is, is light sanding and puting a 4th coat of poly the correct way to fix this? Ive read that the correct way is to start from scratch and sand the whole floor, stain, seal, poly, ect?

Sounds like he didnt rush it witch is good. Did he happen to apply the stain twice or is it a really dark color? Honestly it depends if its peeling down to the bare wood or its just in the top coats. If its peeling back to bare wood its going to take a real heavy buffing or quite possibly a resand, if its just the top coat then he shouldnt have any problems just buffing it down and recoating it. You have to get down to where the failure is in the process and i cant tell you that from here. Is the color coming off with the chips or they just clear?

He stained once. Color is provicial so its dark but not to dark. Most of the chips that are coming are clear

If they are clear then it's in the top coats and should be able to buff and recoat successfully.

if the peeling or blistering is only at the seams it is an expansion/contraction issue more than likely.

the season he stained kept undried stain in the seams between the boards.this gasses off eventually and prevent proper bonding.

if you are actually chipping off the face of the boards opposed to just lines along the seams, then there is a full bonding issue.

I think it is important to know which "sealer" he used.