Robyn's face during montage

Noticed something during tell all part 2 and wondered if anyone else did. When they ran the highlight reel of happier times, watch the wives' faces. Meri, Janelle, and Christine are beaming watching the footage, especially when the kids are on. Robyn is scowling. Then towards the end she breaks out into a huge fake smile, almost like someone poked her and said "hey! Pretend to look happy!"

I wonder what was going through her head. The montage included clips of Kody being affectionate with other wives, so maybe that ticked her off. Maybe she was thinking of her old tagline about destiny and thinking she should have been there.

Thoughts?