Mobile Safari: unresponsive while 'Show notifications' on

[hugginsio]

When starting a cycle on mobile Safari while Show notifications is on, it doesn't start the cycle as expected. Here's the console output:

[Error] ReferenceError: Can't find variable: Notification
	(anonymous function) (bundle.js:443:10258)
	nt (bundle.js:443:10624)
	X (bundle.js:443:8151)
	(anonymous function) (bundle.js:443:10833)

When Show notifications is off, it begins the cycle just fine. Reproduced consistently on iPhone 7+, iOS 13.3, Safari 13.