Understanding Multimodal Failure in Action-Chunking Behavioral Cloning

ArXi:2605.22493v1 Announce Type: cross Behavioral cloning becomes difficult when the same observation admits several valid actions. We study this problem for action-chunking policies and show that different multimodal parameterizations fail in different ways. For latent-variable policies, posterior-prior regularization makes deployment-time sampling reliable, but excessive regularization removes the action-conditioned information needed to distinguish nstrated modes.