Thunderbird icon disappears from the taskbar in Windows 10

[gtoffoli]

I'm experimenting a recurrent issue after adding or re-adding the Thunderbird icon to the taskbar in Windows 10. Some time later, from a few days to a few weeks, the icon disappears from the taskbar. Often, before this happens, for a while the icon itself decays: it is replaced by a generic blank icon.

It isn't a recent issue: it happened to me regularly for years, with many different updates of Thunderbird and Windows 10, up to the present time. I didn't experiment a similar issue with other applications.