I brewed a 5 gallon Maibock lager, and had initial very active fermentation with blow-off that subsided on the second day. After 9 days in primary at 50F, the airlock activity had almost stopped. I brought the lager up to 65F for a 2-day diacetyl rest. After nearly a day into the rest I noticed the airlock bubbling away at 10-12 per minute. Is this normal? Should I wait for activity to subside before racking to secondary? Or should I drop back to 50F and wait for fermentation to complete?