if he is exhibiting this behavior in the tub AND in his viv, that makes me much more concerned. I would contact the breeder first, show him the vid, see what he has to say, and consider returning the snake for a refund/exchange (lemon law; this may require that you take him to a vet to get a vet statement). I know that might be really hard because you guys have bonded with him and done a pretty good job thus far, but it may be a better choice in the long run (this is your first snake, right?).
If refund/exchange isn't an option for you, i would get him to a vet asap. They will be able to tell you if its just a neuro issue that wont cause any long-term issues vs something more serious like IBD.
otherwise, keep feeding him as normal, maybe lay off on the baths

, and enjoy your pet (respectful to his health issues however

)