What version software are you on? The older ones are quite sluggish and the infotainment system slow to bring up the parking display, but yes - I've had situations when things outside are moving much faster than the system can react to.
The most annoying is when squeezing through a tight gap, even at walking pace the proximity alarm goes solid a second or two after you clear the gap. This leaves you wondering if you didn't spot something, but there's nothing there.