There could be a number of explanations as to why that was the case, but, clearly, the body "remembers" or at least can contribute to recall. In HICP work the goal is always full-body engagement in anchoring and recall. Both instructor and student are responsible for at least attempting to avoid any "interference" on the part of the body or distraction caused by tension, extraneous movement or environmental "static."
Best case, following the warm up protocols and systematic practice with the system, the entire brain and body (and posture) should be capable of focusing momentarily on pedagogical movement patterns and anchors associated with targeted sounds and processes. Worst case, it is just "posturing!"