I downloaded Xcode 16.1 beta 2 and this error went away (for me). Hope this helps🤞🏻 (but just remember to submit your builds with the non-beta Xcode. oops 🤦🏻‍♂️)

I am running into this same issue and believe it may be a bug in the beta (or I'm clearly doing something wrong). I am following along the WWDC video and noticed that if I remove LiveActivityIntent & only keep SetValueIntent, my toggle state will be properly updated. However, I then get hit with a Target does not include NSSupportsLiveActivities plist key but I have added the key to both App Target and Extension Target. When I re-add LiveActivityIntent, my live activity begins correctly but my ControlWidgetToggle state does not stay "on". If this is not a bug, any advice from the Apple team would be appreciated. Thank you!

I got here researching something else. Seems related so am posting an Apple Engineer's answer here: https://developer.apple.com/forums/thread/759389?answerId=795157022#795157022

@simonfromhelix thanks for the heads up. for confirmation, are you saying the sharing of the watch face's complications still works and it's just the preview that stopped working? or sharing watch faces in general has all together stopped working? thanks!

@Frameworks Engineer same question but for watchOS 11? Will it still work as well? Thanks!