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I am building a PencilKit app that interprets a canvasView.drawing's size. Drawings below a certain size are interpreted as tap gestures and get cleared in the interpretation process. Effectively, I am doing it like this: func canvasViewDrawingDidChange(_ canvasView: PKCanvasView) { // Check if drawing is empty, // otherwise this would loop guard !canvasView.drawing.bounds.isEmpty else { return } if canvasView.drawing.bounds.width 10 && canvasView.drawing.bounds.height 10 { canvasView.drawing = PKDrawing() handleDetectedTapGesture() } } On my 2020 iPad Pro, this works flawlessly. On other iPads however, I observe a strange behaviour: In a series of drawing little specks on the canvas that are all supposed to be cleared immediately, sometimes the canvas seems to not be cleared, a single speck stays visible. After I draw the next speck somewhere else, the clearing is functional again, which means the canvas was internally emptied, the visible state was just not up-to-date. Finger input on the canvas is deactivated. The canvas tool is set to pencil, width 5.0. Does anybody have an idea what could be the reason for this behaviour?