Violet had a good heart. That's what Greta said.
And that's why August didn't say anything when she rejoined the women. Violet had probably seen Finn by the market when they were at Sylvia's and was nice enough to bring him something to eat. It was a kind thing to do.
Plus, the afternoon with these women had been so wonderful, there was no way August was going to jeopardize that by accidentally instigating a scene where a pregnant Greta ran off into the shadows to kick Violet's ass again. That would be humiliating, and then Finn would wonder why August had said anything.
Finn would see her as a tattle-tale or someone looking to cause a problem, and that wasn't who she was meant to be here. She was meant to be strong—a leader. Not someone who becomes insecure because her mate's ex is bringing someone a sandwich.