Planner Notifications only work for Outlook users?

We have SPO Plan 1 and have Gsuite as our email provider.  We do not get any notifications from Planner when a task is assigned to a person.  We do get email alerts from SPO, so those work.  Since we don't have Outlook, we will never use the O365 group email inbox....but my interest is only in receiving individual notifications about tasks assigned to us.   Does Planner send notifications to individuals that don't have Outlook? 

I have confirmed that notifications are turned off for the group  when a task is assigned or completed, but the notifications are turned on for when Someone assigns a task to me and when a task assigned to me is late. 

I look forward to your insight.

Thank you.