Hi,
here is the demo project.
src.zip contains the objective c code that how I add interstitial, it is compiled and linked into the the lib godot_opt.iphone that is in the Godot_ios_xcode_admob,zip project.
It do not support running on simulator, please run on a device. I have already compiled and linked it, just run the iOS project can replicate the issue, no matter which orientations is the device hold.
the code and project:
I can not replicate this in sample apps.
Here are some linkers for your reference:
doc for how to compile modules on iOS:
and the engine code, I compiled in the 2.1 branch: