...
When collapsed threads is enabled, notifications behave differently - see matrix of scenarios and associated outputs here (full spreadsheet of the chart below)
Desktop Notifications and Mobile Push
...
Notifications
When a user receives notifications about a root post - no change to existing flow. Take the user to the channel, scrolled to the root post
When a user receives notifications about a reply post in a thread that is followed, take the user to the thread in the Global Threads context
When a user receives notifications about a reply post in a thread that is not followed, take the user to the thread in the Channel context (RHS)
...