Reaction of slight bowel bleeding with Vitamin C

Whenever I take even small amounts of Vitamin C (50 mg) I get small amounts of blood in my stool. I've tried many different forms lipo,'Allergy C formula' buffered, Palm and cherry derived etc. Palm and Allergy C were better if I only use once in a while, not multiple times in a row. I wish I knew why this was. I have had an duodenal ulcer before but feel that it is well healed.

I have food sensitivities to Gluten, nightshades, caffeine and avoid those and eat Paleo with low fruit/sugar, low dairy (only butter) and low non-gluten grains.

Non-GMO (mostly Organic) Corn is one grain I have been eating and now I am wondering if I have a sensitivity to corn.

I also believe I am suffering from silent acid reflux /GERD, lots of nasal drip, which I believe is related to a Histamine Intolerance . I have to eat low histamine foods strictly for periods of time and then be careful not to eat too many high histamine foods ongoing.

Anyone know why Vit C would cause slight bowel bleeding?
Anyone know forms or brands that might work for me? Tweet