SwiftUI render wrong size on old devices like Apple Watch Series 4

Problem:

SwiftUI render wrong size on old device like Apple Watch Series 4.
The height was be cut, not well render as series 6 or simulator.

Check the screenshots.
BTW:

But it works well both on watch series 6 real device or simulator.

Reproduce:

Download “Build a Workout App for Apple Watch”, run the code on a real device of watch series 4 https://developer.apple.com/videos/play/wwdc2021/10009/

On Watch4-44 mm (first line be clip)

On Simulator or watch 6.