Update: If you're having trouble with the Windows 10 taskbar icon, be sure to intall the Latest Update.

Author: Alexis

Remove currently pinned taskbar icon, run MusicBee and then pin the icon from that instance of MusicBee.

This seems easy enough that I thought I could handle it. Note that this happens to a lot of programs on windows for a variety of reasons from pinning the wrong shortcut to reasons related to version changes, so I would not consider this a MusicBee problem.