Yes, this is a common occurance with lots of hardwood floor. Your rh seems to be in the perfect zone though. So, the inspector is going to come in with his thermohygrometer and you better make sure that rh is up there and not even borderline. I do these inspections as well.
Like you mentioned, if they sell it there, then they should accept your zones rh.
Also, you can ask, how was the wood stored in the HD? Check the stores rh and there you have some ammunition. Except for the fact the wood might have been wrapped in celophane in the box. This keeps the MC of the wood in check while in storage. If not wrapped in protective plastic then I would ask what the difference is in them storing it or you putting it in your house under similar conditions.
Either way expect a fight on your hands. Run down to a store and buy a small humidifier, it looks good on the report. Don't give the inspector the reciept so he can check the date.
Other than that, all I can tell you is exotics do split and check and finish check more than others. Was there anything written on the box or in the installation requirements as to the ambient rh and temp?
I just did an inspection on a very common solid 2 1/4 x 5/16 x random red oak fastened down on ply. No checking, no splitting, no finish checking, just some small gaps between the strips because the rh was only 19%. So you see the difference?