Thye only thing I see for the 2.7 is a TSB relating to "intermittent
hesitation." When I first learned of this issue (prior to the TSB being
issued), Hyundai referred to it as "very infrequent engine cutout" and
described it as feeling a jerk while driving because the cutout was so
momentary. They didn't (and won't) share the specific conditions which
must be met for the stalling to occur, so I don't know whether it's
possible for it to occur at a stop. I'd think it's a longshot, but I
don't see anything else to point my finger at either. Most likely, it'll
require a technician to experience and diagnose the condition while it's
occurring.