I am probably as far from a flat clapper as you can get!
Yes it is an issue with not just Haltech, motec m800 and earlier, link etc all suffer from it.
With a good CAS and good signal wires PFC, Nistune and Adaptronic won't suffer from it, if you get really bored you can listen to a youtube video or post Andy from Adaptronic made about it too. So for a plug in ECU designed for that engine I think it's a rubbish ECU choice if you need to fit aftermarket sensors.
It's always to learn something new