notifications - How do I set Android’s Clock app to vibrate for timers?

When I set my Android to All Notifications Vibrate mode and set a timer with the Clock app, the only notification I get is an on-screen display of the time counting negative past zero. There is no vibration, so I can’t tell that the timer expired when the phone is in my pocket (especially when using headphones with my computer). I can’t figure out how to ask the Clock app to vibrate the device when a timer expires. How do I enable vibrations for this notification? If this is a bug, how do I report it most effectively?

Normal notifications such as toasts will generate a vibration so that I can tell there is a notification when the phone is in my pocket. The normal alarm function of the Clock app will vibrate the device just fine.

I’m using Clock-4.2.1 (2383161) on Android-5.1.1+OxygenOS-2.1.2 on a OnePlus2.