Symbol timeline not in sync

Hello I'm making a character cartoon with an armature compromised of several different graphic symbols. One of these symbols is the head which contains the mouth symbol and animation inside. The problem is the armature timeline and the head symbol timeline are not in sync but it isn't a set number of frames off but is is quite inconstant. The lip syncing is perfectly in sync in the head symbol but it isn't in sync in the main timeline. Please help.