Bamboo Flooring - Bowing Before Installation

We just purchased bamboo flooring for our house and are giving it a few days to acclimatize to the humidity and temperature within the house prior to installation later this week. We just unpacked it yesterday and today I've noticed that some of the pieces are starting to bow slightly.

Is this normal? Should I be concerned? Is this an indication that the humidity in the home is too high/low? I'm in Saskatchewan, Canada and this is a new house with an air exchanger. We haven't been running the furnace much lately.

Brandon