Main Floors uneven after attic conversion
Humidity swells boards.

When this happened to us it was because of humidity.  It was mostly around the air conditioner ducts, where the cold air caused condensation.  The boards heaved right up because they swelled with water.  There was mold too.

Our problems were 1: opening windows at night in the summer. 2:  drying clothes on a line indoors. 3: running the fan all the time.  

Tying your issues to the attic conversion - if you were losing humidity thru the attic and your attic renovator installed something new that prevented the loss of humidity you had before, then your house might be more humid.  The humidity is swelling and buckling the wood.  Or humidity might be unrelated to attic project.

Once we fixed the humidity most of the wood went back down.  I set heavy stuff on some to press it into place but we needed a guy to come remove and shorten some boards that were now too long to go back in place.