I have done all the steps just like you, but I still can’t reproduce.
In addition, the switch between Speaker view to Gallery view from desktop app is your desktop behavior, which should not affect the ios SDK.
I guess it has something to do with the phone and the iOS system. Can you change the iphone to try again, what’s your SDK version? 4.6.21666.0428 if not please go to https://github.com/zoom/zoom-sdk-ios to update , and then try.
I am also very confused