I've noticed that many Macs have have applied the latest El Capitan Security Update have started to have problems with their Apple bluetooth Magic Mice. The usual symptom is that the computer forgets the mouse and is unable to re-pair it again without a LOT of hassle. It's been happening with the newest Magic Mouse (with the lightning cable charger) and the previous models that use replaceable AA batteries. Batteries have been charged and replaced as applicable in an attempt to fix it.
Is anyone else seeing this?