Update: The problem should now be resolved. Watch apps should upload as normal once again.
Developers are flocking to Apple’s developer forums today as the iTunes Connect submissions process is currently experiencing a glitch which makes it impossible for developers to submit apps that include Apple Watch extensions.
Rather than continuing submission process as normal, the system is incorrectly flagging up misuse of an Apple private framework called SockPuppetGizmo. Naturally, this is causing frustration in the developer community at the moment because it prevents apps from being submitted to the App Store.