There is no problem with the phase animator. If I do this struct ContentView: View { @State var img1 = UIImage(systemName: "gear")! @State var img2 = UIImage(systemName: "gear")! var body: some View { PhaseAnimator([1, 2]) { phase in Image(uiImage: phase == 1 ? img1 : img2) .renderingMode(.template) .foregroundStyle(.white) .background(.black) } } } It exactly does blend as expected. It blends two images (with identical content) and you will not see a pumping effect. The problem starts, when I create an UIImage with UIGraphicsBeginImageContext like with the resize function in my first post. Then the two identical images are pulsating. PhaseAnimator([1, 2]) { phase in Image(uiImage: phase == 1 ? img1 : img2) .renderingMode(.template) .foregroundStyle(.white) .background(.black) } .task { img1 = self.resizeImage(image: img1, newWidth: widgetSize) img2 = self.resizeImage(image: img2, newWidth: widgetSize) } (And yes, UIGraphicsBeginImageContext is deprecated, but it does not matter, the same behaviour can be observed using UIGraphicsImageRenderer)

The Xcode Cloud TestFlight Build setting was set to "Latest Release or Beta" and Apple had updated its tool chain to Xcode 15.3 beta 2 (15E5188]) Switching back to Xcode 15.2 (15C500b) solved it.