Here to say that it worked for me as well! My problem was that my main target was built for iOS 18.2 and the extension was built for iOS 26 and I was actually running 18.5... Having set the deployment targets to iOS 17 - everything worked like a charm again.

Here to say that this solution worked for me as well! My problem was that the main target had a deployment of iOS 18.2 and my extension was iOS 26, while my simulator is running 18.5.. Having set everything to a target of iOS 17 - everything started working like a charm again.