[Chaos]

You can stack ALL resist with specific elemental resists in order to trigger the momentum loss. For instance, if you had Sayakana and fully-ranked Golden Glow active with Brighter Darkness (20% ALL + 5% Light), anyone who tries to smack you with Light damage will trigger a RESIST message.

Given that all other nonspecific resists, such as Physical Resistance/Magical Resistance, do not cause momentum losses, I'm inclined to believe this is a bug.