I don't understand how StreetPass works.
Yesterday, I was carrying both my 3DS and my 3DSXL. My 3DS got a Mii Plaza tag for someone called Rhe. It showed she last played Animal Crossing. My 3DSXL got a StreetPass from Rhe as well - but only in CrossworDS Plus. Not in Mii Plaza, not in Animal Crossing.
Today, I had my 3DS, my 3DSXL and my friend's 3DS in my car. We got a StreetPass from both a DRAKE BELL and a Kay - but only on Mii Plaza.
My 3DS got the following:
DRAKE BELL - Last Software: eShop
Kay - Last Software: eShop
My 3DS XL got:
DRAKE BELL - Last Software: eShop
Kay - Last Software: Mario Tennis
My friend's 3DS got:
DRAKE BELL - Last Software: Paper Mario
Kay - Last Software: eShop
Later in the day, I was carrying my 3DS and my 3DS XL.
Both systems got a Mii Plaza StreetPass from Riyo.
Only the 3DS got a Mii Plaza StreetPass from Crash.
All three Mii Plaza StreetPasses show Animal Crossing as the Last Played software - but no Animal Crossing StreetPasses.
Just so weird.