How can Transit app vibrate my phone even with notification sounds turned off?

I've been tweaking my notification settings for various apps recently, and today I noticed something very peculiar. I was using the [Transit App](https://transitapp.com/) in **Go** mode as I do on most days. As I approached my destination, I felt my phone vibrate... but I had already turned off Sounds in the notification settings for this app! *(See below)* I'm sure the vibrate was from Transit App because I had exactly one notification in my Notification Centre right after I got the vibration. Is there any way to suppress vibrations from app notifications, since apparently turning off sounds doesn't do it? Additional info about my phone settings: - Silent switch: Off - Do Not Disturb: Off - Vibrate on Ring: On - Vibrate on Silent: Off - Ringer volume: 50% - System Haptics: On