(Automation: Appium\Java) (Xamarin Forms\iOS 13) Elements not visible in tree, after in-app downloads

Summary: We have a Xaamrin Forms iOS\Android application. My goal is to make auto-tests for iOS-app built with Xamarin.IOS 12.10 and Xcode 10.2.1. Builds are made by App Center. Target iOS versions are: 12 and 13. Testing must be performed on real devices, so I not bothered with simulators.

Problem: on devices with iOS 13 element tree contains all elements correctly, i.e. Appium can see all elements and interact with them. But, after “synchronisation” (Which is in-app download of database from server. It’s necessary for application to work) element tree reduces just for 2-3, each representing a whole screen. So tests cannot find particular elements and fail. Strangely, but on iOS 12 things go smooth all time whether app made download or not.

Appium versions used: 1.15.1 - on local machine, 1.11 in App Center (though I suppose they’ve forked it somehow, but it never explicitly said in documentation) Problem oсcured on both versions.

Questions: How elements can become inaccessible like so in general? What is most probable source of problem in this case particular: iOS, Appium, maybe app itself? Did someone encaunter this or a similar problem? Is there a working solution for it?

Here are links to page sources that I managed to get from tests. I got theese two from same device iPhone XR, iOS 13.3, Appium 1.15.1

Normal Element Tree: https://drive.google.com/open?id=1G82n1xYAxiMQ3q-VV22NXCarM_2dXws3

Element Tree After DB Download: https://drive.google.com/open?id=1nywD3ShSdb1lDbN77mGB6WW018RNjO4F