There is a path today for customers to request their test/dev environments to be patched before prod which will allow them to test the release prior to patching. If a customer identifies an issue they can also request to postpone their prod upgrade. The details of this process are outlined in the update notification, and it can be done once for all future updates. 

Having said that, OAC is not a CM service and not an OMCS hosting service, for customers that would like to have complete flexibility on their update timeline we offer OAS and we are working on simplifying the deployment of OAS on IaaS. Similar to other cloud services, upgrades are inevitable - we definitely will not update an instance knowing that it will cause customer issues, but absent of bugs - upgrades will need to continue on regular basis. It is required both in order to maintain our ability to manage tens of thousands of instances, as well as the overall health and security of the fleet. 

Going back the the first point, I do advise that customers that need to, will take advantage of the ability to create an upgrade schedule which accommodate their UAT/Prod needs (which is the original ask here).