Greenbean skin turned red?

I've had an uncomfortable feeling in my gut today. Nothing too extreme. I went poop today and a check of my stool showed some mucus and an undigested piece of green bean skin that was now red. Like rose colored red! There were also some smaller pieces of green bean skin scattered around that were also red. I'm sure it was green bean skin as it had the burned marks on it from last night. Has anyone heard of green bean skin turning red?