Same here, about 1 turn or so to re-tighten them all. I found one or two even much looser, as the nuts were backing off. As said above, the trailer is just settling after being built. Happens to lots of things. It is probably to the wood floor drying out a bit and shrinking. One of those good things to put on a yearly checklist!
2015 Starcraft Travel Star 299BHU Black Pearl Edition
2011 Jayco X23J (traded in)
2009 Ford F150 FX4 SuperCrew