I realise that this is a very minor issue. The Avast Secure Browser task bar icon is not visible in Bank Mode, just a grey square. It has only happened with one onf my three Windows 10 devices, it being visible on tow of them.
I guess that the task bar icon is intended to be visible which is why I have reported this. Secure Browser seems to work OK otherwise.
Secure Browser Version is 106.0.18815.119 (Official Build) (64-bit)