(Poorly planted) evidence or not, there are more people telling Asami that Mako’s some crazy plotter than people telling Asami that Mako’s the good guy. Even Korra assumed the Northern Water Tribe blew up the Cultural Center.
Sadly, I think we’re supposed to believe Asami is doubting Mako, because that’s what that “look” says to me, with Asami glassy-eyed at the center of Mako’s now-empty apartment. Since this is also the last shot of Asami in the episode, it could also be picked up later and Asami’s “look” explained by her actions, but that sinking “No-Asami-Don’t-Believe-The-Lies!” feeling you got was exactly what the show was shooting for.
-Da7e-