I have laid click Morning Star stranded bamboo. It has gapped in the same place twice (fixed once). It seems that the gapping follows the line of the heat ducting in the basement below. Is there anything that can be done to prevent this short of rerouting heat ducts or scrapping thousand of dollars worth of flooring?

its called a hot spot and can effect glued, nailed flooring as well.

exotic species be very susceptible to it.

you can try insulating the duct..and look into a deflective material possibly foil.

The click strand is a touchy animal, make sure to check the rh in there. A stand alone humidifier might help. Order it off amazon. I paid like $180 for mine and its cheap for the investment you made buying that product.
Have they put the rh and temp requirements on the instruction yet? lol