Had Severe Diverticulitis Previously. Had Partial Colon Removed. Passing Bubble During Bowels. What Could It Be?

Have a question for you. A year in a half ago I had severe diverticulitis I had a portion of my colon removed after surgery everything went well went home after a few days then I noticed when I had a bowl movement there was a bubble that would come out I asked my surgeon about this and he said come in in a few weeks if it don t go away this is common after this kind of surgery, a few weeks later I went back to see him he did a rectal exam and said he does not see anything increase my fiber intake well months went buy and it is still there so I went to another doctor for his opinion he did a exam and said is probably a hemmoriod you have them on both sides of the inner rectum so he put bands on both of them and said they should fall off in a few days, Well it s been 8 months later and the bubble tissue still comes out when I have a bowl movement It does go back in when I m finished but no doctor seems to fiqure out what it could be. Any input on my situation?