Popovers are meant to be shown as sheets on iPhone. If you run the app on an iPad or a Mac if its a universal app, you will see it display as a small overlay as the name suggests. Hope this helps.

Same problem here. Threads on other sites suggest it's a drive space issue but I have over 200gb free. This is very frustrating. Same result with other versions of iOS. Next I am going to try to download an Xcode beta version to see if it works.