Thank you for reporting the bug.
Is she drawing aggro only when she is using Crescent Phoenix or always? Also, check if she has a shield on as it increases a character's Threat. I will look deeper into it on my end.
She's currently drawing all aggro even when I haven't used Crescent Phoenix. I know it's not her shield because I removed it and the problem remains. I also double checked her shield and there's nothing in it to increase aggro on her. I only use such a shield on Ryu.
I also ran into another bug. The game crashes after a campsite scene where Ryu speaks to Nina. This only started happening when I got her trust level up. The dragon tear is white looking. I guess this new color replaces the original rainbow color? At this point, Nina asks Ryu of their bond and if they're family. The game crashes every time after I choose the "Our bond is unbreakable" option. This seems to happen 100% because I restarted to the game 5x so far to test this and it keeps happening if I select that response option. The game doesn't crash if I choose the "We're family" option. I haven't tested this with Lin yet, so I'm not sure if it happens to her as well. 
I found what is causing the issue for the crash and a secondary bug. The crash is happening because that specific response is trying to find the player data from a previous patch (player location variables store when you go to camp). I must have missed that one as the remaining ones (even Lin's) appear correct/updated.
Looking into the Dragon Tear branches I also found the tear is flashing white every time instead of the correct color because I used the wrong sign at the final "Love" check (used less than instead of greater). The white flash is supposed to be when you are over the max of 600 Love.
I greatly appreciate you taking the time to play the game and reporting bugs and giving me feedback. I am sorry it is a bit buggy and will continue to keep fixing the bugs. I do play and test the game as I go, but unfortunately there are things I miss.
I greatly appreciate you!