I've been on the phone with Apple support for a while and we think we have identified a significant issue with all of the new watch faces. None of my third party apps and also a lot of the native apps (e.g., mail, messages) are not able to be added as a complication on the new watch faces. However, they all are able to be added as a complication with the old watch faces. I haven't tried every complication with every new watch face, but I have tried enough to know there is an issue. Also, I've tried this with multiple Series 4 Apple watches and they all have the same result. Is anyone else experiencing this issue?