First, I have to assume you're dealing with blood in your stool, not urine.
Please correct me if I'm wrong.
In any case, you might need a scan to verify its location.
Check this out:
https://www.mayoclinic.org/diseases-conditions/gastrointestinal-bleeding/symptoms-causes/syc-20372729
In no way should an AUS cause bleeding unless the surgeon created a bleed. Whether in urinary tract or bowl.
Good luck in resolving this problem.