I still get this on all my Simulators, iOS14.2. Not on my real devices, iPad Pro 2015 and iPhone XR ...

As of today this affects me all of a sudden. Running on my iPad Pro 2015 no problem, but when debugging on my iPhone XR the app hangs about a minute on the launch screen and then starts. Then all is fine, but on the next build and run, the same thing. I deleted everything in the library/developer folder, but that did not help, nor any of the other solutions posted here. Would be grateful for a solution ... Big Sur, Xcode 12.2, devices on 14.2

Anyone?

@Claude31 Coming from iOS14/iPadOS14. The provided error message is the complete message. Like others mention above, it has to do with the keyboard appearing. It has nothing to do with self set constraints. In fact, it happens without even a ButtonBar (or ButtonBarButtons) present! App works normally, so the user does not experience any of it!