I remember D&K and Charla & Mirna doing the 1 and 2 in All Stars (twice), and I remembered the lets Russian leg that Jodi & Christie won with Kisha & Jen in 2nd (thank you earlier flight) but I couldn't remember their names during the broadcast.
I honestly think this is only the fourth time its happened. But I could be wrong.
I can confirm it from checking every race. the closest that it came was in AR8 ep.7 when the all-female Godlewksi sisters finished first and the Weavers (mother, daughter and Rolly) finished second. However, you have missed one from AR11 because there were 3 legs where it happened:
ep. 5 Charla/Mirna first, Dustin/Kandice second
ep. 9 Dustin/Kandice first, Charla/Mirna second
ep. 11 Dustin/Kandice first, Charla/Mirna second
Your AR14 example is correct. Christie/Jodi did win ep.4 with Kisha/jen second. There were no others from AR14.
That is it, a total of four. What was your 4th one?