Registered animation won't play

[OH1972]

I am positive and have verified that I have a host of animations for Riekling boar riders registered via SLAL. But while other Riekling animations very much play, I see a debug message from the triggering mod in console that while the Riekling Rider was a valid creature, no valid animation was found. 

Registered animations include Anubs Boar+Rider, Anubs boar_breeding+rider, 7 versions of Billyy (Boar + Rider)

 

I'm at a loss what the issue might be, since evidently, other Riekling creature animations are being loaded.