Hello,
I had same issue and there was someone else who inquired about same thing on this forum back in July and a solution was provided:
Please try the following steps:
>> Clear the Teams cache:
- If Teams is still running, right-click the Teams icon in the taskbar, and then select Quit.
- Open the Run dialog box by pressing the Windows logo key +R.
- In the Run dialog box, enter %appdata%\Microsoft\Teams, and then select OK.
- Delete all files and folders in the %appdata%\Microsoft\Teams directory.
- Restart Teams.
She mentioned if folders exist in both Local and Roaming then to delete the files in both.
I followed this and it worked. I still see New on the icon, but now when I have new pings, I see the info as well.
Here is the original thread: New Teams app is not showing all notifications in the activity feed - Microsoft Community