I've never heard of it causing indigestion, unless you get carried away with the munchies. It's used as an anti-nausea treatment and for Crohn's Disease, which covers both ends of the digestive tract.
Smoking is dangerous for health and has lot of health effects. Smoking causes cancer and many other diseases so we should avoid smoking.
The key reason it may cause in digestion may be the smoke is ingested when inhaled. And also helping to cause indigestion, smoking increases your chance of developing lung cancer , chronic bronchitis and emphysema.
No, the reason for the indigestion can be linked to sugar consumption. Cut out all sugars, including fake sugars, which have much worse side effects and see for yourself. As Buzzby mentioned, weed is medicine and good for the body.