Frequently what is the case is that the Apple Watch complication, for example, on sleep says something. Like today it says 75. And then I click on it. And for a brief moment in the app it says 75. And then a few seconds later it updates to 80. And then when I go back to the watch face it still says 75.
At times, what is on the Apple Watch also can disagree with what is in the iPhone app.