[20.19] Require PIN code to pause activity

When using the Device Passcode feature, the passcode is required each time when the watch is detected off of the wrist, or after an extended period of time has passed since you last entered it (which is typically around once a week). If you're wearing the watch over your sweatshirt, then it will not detect your wrist-based heart rate properly to determine if it's been removed from your wrist. That would explain why it's asking for a passcode when pausing those activities. 

For proper fit guidelines, visit Garmin Watch Optical Heart Rate Accuracy Tips. And for additional information about the Device Passcode feature, visit Using the Device Passcode Feature on a Garmin Watch.