Updating to watchOS 9.6: "update iPhone first"....but I have
I've updated my iPhone 14 Pro Max to the latest releases of iOS, 16.6. When I came to update my Apple Watch 5 to watchOS 9.6, I put it on charge, as usual, opened the Watch app on the iPhone, and selected General: Software update, but got a message saying "To update your Apple Watch, you first need to update your iPhone. You can update your iPhone software in Settings." But the iPhone has already been updated. I tried restarting both watch and phone, but to no avail.
Apple Watch Series 5, watchOS 9