The Sonos Controller for my iPhone X freezes up the instant it is opened. It might register a button press but 99% of the time it will completely freeze and eventually crash (restarts itself). Reopening the app causes it to happen all over again. I've tried deleting the Controller and reinstalling to no avail.
iPhone X / iOS 12.1.2 (16C101) / Controller ver. 9.3.2 (according to the App Store)
iPad Pro (9.5") / iOS 12.1.1 (16C50)