that doesn't sound like dumping. I know of someone else who has SIBO - (small intestine bacterial overgrowth) that sounds somewhat similar to what you have, but I'm NOT a medical person. I've also heard of people having issues digesting carbohydrates (not necessarily WLS patients, but I've heard about it in WLS patients, too) who have to eat a low FODmap diets (or at least very low carb diets) to control it.
I would see your general PCP - and if they don't know, maybe they can refer you to a G/I specialist. These kinds of things aren't really common, so it could be that the people at your bariatric clinic just aren't familar with it.
EDITED to add: I just re-read your message and noticed you said you've had liver problems, too. Maybe it's related to that? I would see if you can get a referral to someone who deals with these kinds of things (G/I person or maybe a hepatologist (if it's liver-related). At any rate, I'd probably start with my primary care covider.