At least monthly spotify becomes unpinned from my taskbar. It seems to happen everytime there is a new update to the app ready to install, but before it is installed. It only started happening 6 or so months ago when I switched to the Windows app.
No other programs become unpinned including other windows apps, wolfram alpha and calculator.
Spotify ver. 188.8.131.520.g1fcff12a (Windows Store version)
Windows 10 Edu. ver. 16299.248