I have had this jerks countless times...most times mine happens in church as I doze off. Suddenly it strikes me and I jerk.
Since it happens mostly while I sleep in church or any gathering, I just feel maybe it's normal due to the disturbance from the loud microphone or speakers.
You are one of those who doze off in church... you must have experienced it for sure. Thanks a lot for reading my post. I am glad you did