The 18th Abn Corps is a HQ element for many non-airborne units. 10th Mountain, 101st (Air Assualt), 3rd ID, etc, etc..... That being said, tyrsnbdr is probably correct in the statement that she's probably reassigned to them for tracking purposes. Who knows, maybe someone on Ft. Bragg could explain it further.
I'm not sure but I do believe that some units in the 101st still wear the maroon beret. Each infantry division does have it's airborne assets, usually LRSD.
My last duty assignment was in the 25th ID(L) and we had a LRS detachment on post and they had the airborne tab above the division patch. I don't recall seeing them in maroon beret's though. 3 1/2 years went by too quick in paradise.
I'll have mine on within the next 6 months (with jump wings on the chest). I'll be going to 7th Group (Non-SF), what battalion I don't know, I may be unlucky and go to the MID.