Yet more confirmation, as if any were needed, of the hazardous nature of the call "Positive rate" - which is a VSI function.
It is surely far safer and more prudent to change the mindset a little and use "Positive climb", an altineter based call that eliminates a false call ffrom either a bounce or poorly damped VSI and predicates the gear up only once the slower reacting altimeter has started to register a change of altitude.