For longer time I had 1 unread notification icon for some invisible thread:
I checked today in Web Monitor (F12), and response for this request:
forums.garmin.com/api.ashx/v2/notifications.json?IsRead=false&PageSize=1&PageIndex=0
was returning 1 thread (despite it being invisible on a webpage):
Opening this link from JSON finally allowed to read that thread from that 1 notification and the icon disappeared.
Looks like there is a rare bug when there is notification icon without displaying thread.
Don't know why this happened, maybe ExpirationDate was wrong, but it would need checking how it looks for other correct notifications.
ExpirationDate: 0001-01-01T00:00:00 CreatedDate: 2020-04-21T11:08:39.783 LastUpdatedDate: 2020-04-21T22:12:37.133 IsRead: false