Are the white lines along the long edges of the planks? From what you describe my guess is that the wood shrank (all wood does) and the polyurethane (waterborne...yes?) stretched and turned white. This is just a guess, but this is called "white line syndrome". It does not always happen with every floor that is finished with waterborne polyurethane, but some floors, especially wide planks will exhibit this symptom. What your guys are doing is what I would do...dig the offending finish from between the planks and recoat. It probably will be fine in the end.

I know this thread is a bit old but I wanted to chime in as people are continuing to debate and google-search the decision between wood floor and wood-look tile. I am a Realtor and I don't think this is necessarily "just a trend." Wood-look tile is continuing to change dramatically and can be quite impressive! I often see investor-flipped, new-construction, or standard pre-owned homes/condo's with updates, etc. In the past year, I have seen a big increase in wood-look tile. Sometimes it looks good, other times, just okay. When it is of lower quality, you may as well just do a cheaper tile. I absolutely think laminate is on the out, unless you are getting a higher quality. If you go cheap, it looks cheap and feels cheap. Families today often want updates, nice finishes/fixtures, and the idea of also having something that looks great, but also durable, is a big plus! So, I would say, go ahead and do wood-look tile, BUT, do it right! Invest in the higher quality product and be sure to take in consideration the grout color. A lighter color looks more obvious AND you have to seal it to help keep it clean. A medium-darker color is less obvious and easier to keep looking good year around. I am in the Fort Worth, TX area.

I have vinyl plank with huge dogs in my walk out basement where they have free access to a large dog run it has been in for 11 yrs and still looks awesome. We have a laminate on our main floor that looks like slate and has also stood up to the brats for 11 yrs there is no way wood could have handled all that abuse. IMO laminate or vinyl plank in good condition is better than scratched up wood floor that would have to be refinished before sale. We now have a great pyrenees as our 2 old dogs have passed away and he really is rough on floors , no wood could possibly stand up to him.The pic is the laminate floor and the old dogs

We have a similar tile around our wood-burning stove at our cottage. The walls of our cottage are light pine, so we went with darker brown (that matches the knots in the pine wall) engineered wooden planks. Then we used slate tiles around the fireplace. This is the best pic I have on me, you can see it a bit.