Hi James! I’m not 100% sure but this sounds like a bug if it is only occuring on iOS 12. If you create a new, blank test application with that same “User is logged out” --> Go to other page workflow, does the same behavior occur when testing on your iPhone?
I sent a bug report 3 weeks ago with an example. The first time you open Safari, Bubble go down and does not use the user information. It blocks any action from the initial workflow (page is loaded). No ‘workflow’ is executed. By doing a ‘refresh’ of Safari everything comes in order. I am waiting for the resolution of this issue. I don’t know if it’s the same thing in your case.