(Radar already filed, posting here for others / visibility)
iOS version: iOS 17.0 (21A5277j)
Xcode version: Version 15.0 beta 4 (15A5195m)
The problem: When a Spring animation with a speed modifier is applied to a view to animate an offset, AND a DragGesture is used to affect that offset, AND the user triggers a second DragGesture before the animation from the first completes, all future animations have strange end states and ongoing jitter.
How to reproduce:
( 0. Create a new Xcode project and replace the file ContentView with the attached file.)
Run on a device (I used an iPhone 11 Pro)
Drag the purple box down, then release it.
Before the box has finished animating back to its starting position, place a finger on the box and begin dragging it down again.
Release the box.
Expected: The box animates back to its starting offset and stays there.
Actual: The box animates back to its starting offset, then jumps to a new location. If you watch closely, it may then continue to move around by a few pixels. Also, the text inside the box does not correctly follow the container animation. Note: this only occurs when the speed modifier is applied to the animation. If you toggle this off in the code sample, you will see the animation behaves as I described in "Expected:"
ContentView.swift