Over the past several months I've noticed a few cases where, when I run the 1Password app on my Apple Watch, it would take 5-10 seconds before showing any items. About a month ago (maybe when I installed iOS 12 on my phone, not sure) it started showing a screen which says "Add items from 1Password on your phone, Requires Apple Watch Passcode", until I unlocked my phone, and then the items showed up. I figured the watch wasn't actually holding the items anymore and it needed to download them from the phone - maybe not the most useful thing, but ... okay.
My new iPhone XS arrived on Tuesday, and my new Apple Watch 4 arrived yesterday, so I've upgraded both devices. Now, the watch app isn't showing any items at all, whether the phone is unlocked or not - the only thing it shows is the "Add items ... requires passcode" screen.
The app on the phone works perfectly, items are sync'ing in both directions with the various laptop and desktop machines on my 1Password accounts (family account for personal stuff, team account for work).
I mostly use the watch to get TOTP codes for a few web sites, and while I can certainly get those from the phone, it's not as convenient as using the watch.