[aerohead]

I've yet to find anything official, related to this so-called 'separation trap.'
It may be a situation where a journalist has mis-identified an extant device and has attributed it to the IONIQ-6's head of design at Hyundai; who, while mentioning the aerodynamics folks who cheated ten more counts out of 'Prophecy' shape, failed to mention the elusive 'trap' as a component of their bag-of-tricks.
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Any rear spoiler which lofts its tearing edge up to the 'reversal point', is, essentially capturing a separation bubble, which will travel with the car as a dynamic feature.
The dual rear spoilers on the '6' probably aren't as effective as the 'tea-tray' spoiler on the Prophecy concept, but work in that direction.
Maybe the Prophecy was too 911-esque for management's comfort. It certainly suffered the 911's rear shortcomings.