Thank you for the query.
The most probable reason of intestine perforation is colonoscopy
. During this procedure, large intestine is filled with the high pressure air like a balloon. This high pressure in some cases when intestine wall for some reason is impaired causes perforation (especially when diverticles are present). Sometimes during the colonoscopy polyps are removed which can also cause such perforation.
As you can see, colonoscopy is not 100% safe procedure and such complications are always possible.
Hope this will help.