Mmmmm, a new bass on which the back bow is so severe as to stop the strings vibrating below 7th fret has experienced more than some subtle changes in temperature/humidity (even if not tuned to pitch), it's been poorly built, even if the extent of that poor QC is a bridge that's too low or a neck that's at the wrong angle to the body. If it were a solid body on which it's easy to adjust things like string height and action, and even to shim the neck, I might advise a bit of experimentation, but not on an acoustic in which the options are generally far more limited. Back to the manufacturer with it quickly