Does excessive movement to cover one's awrah during bowing (ruku') and prostration (sujud) invalidate the prayer?

A woman's covering of part of her neck during prayer is obligatory because the neck is considered 'awrah (private part). The exposure of a small part of it does not invalidate the prayer, but one must promptly cover it. Movement to correct the prayer does not invalidate it, for not all excessive movement nullifies prayer. Indeed, movement may be obligatory if the validity of the prayer depends on it.