Glad to know I'm not alone, but this is the first time I've noticed one. I have 5 reservations on hold and this is the only one that received an eTDS e-mail.

The only thing I can figure out is that this was part of a nested set of itineraries - I'm picking up a child who is too young to fly as an unaccompanied minor.

AAA-BBB (Itin #1, me alone)
*BBB-AAA (Itin #2, me + toddler)
*AAA-BBB (Itin #2, me + toddler)
BBB-AAA (Itin #1, me alone)

I booked them this way for convenience, even though technically it could be an illegal booking if I was trying to avoid minimum stay requirements. I wondered if this was a 'red flag' e-mail.