Gut issues are massively complicated in each individual. Are you still taking your PPI's every day? It’s important to continue with them until you can detect what could be causing your symptoms, usually bread and milk are the culprits in lots of people as we age.
I agree, age should be taken into consideration when one has these procedures, I and my husband both suffered with Gastritis after having a colonoscopy and still have to be careful what we eat, so I do think it's related to being prodded about inside and with age, it takes weeks to feel better again.
Just to elaborate, we both suffered from gastritis from the colonoscopy prep, but my husband suffers from lifelong IBS and that condition got worse after the prodding about, at least that’s what we put it down to, but he did recover well after a few weeks and is managing the IBS with his diet.