After upgrading my iPhone to iOS 15 the 'ZendeskSupport' app is no longer clearing notifications. It is set at '99' even when I do not have any outstanding notifications in the online or mobile platform.
I have uninstalled the app, restarted my iPhone, and then installed the app, but then the notification issue reappears.
(Screenshot below)

This is currently being investigated. I'll create a ticket for you to keep track of it.