Even as someone who is Bisexual yeah I don't really remember any majorly obvious hints off the top of my head. Maybe they had some kind of Bisexual Lighting (Using Blue/Purple/Pink lighting on a character) at some point that I'm just not remembering.
"@Background Pony #8C1B":/images/2632840#comment_9674831
It is surprising to me that they allowed that confirmation for Sombra but didn't do it for Rainbow Dash and Applejack which is both more obvious in show (as in
it is at least argua ble from the conversation they had in The Last Problem) and it has the same kind of Twitter confirmation