I posted last week regaurding cracking boards. Since then I have discovered that my humidity is around 44% , also some extra boards that were not installed,but stored in spare bedroom are also cracking or checking. Does this sound like flooring was too wet. It was enginered BC , from China( I know I was probably dumb,but the price!!! Please give me some ideas what is going on. The flooring store will probably replace if it is defective wood.

44% RH is within normal range. What was it when the flooring was delivered, acclimated and installed. IF the humidity was really high and the flooring swelled, then it was installed and now is drying out, that could be considered faulty installation. But since you have other wood that was not installed cracking as well, I'd have to guess that flooring was not properly kiln dried. If the store is willing to replace it, go for it. Will they pay the labor to remove the existing floor and install the new flooring? It would be great if they did but I wouldn't count on it. Material replacement is usually all you get, if anything. There are a few good manufacturers who will pay for labor as well.