Inputting "Nb bass" chord symbols

Though it doesn’t appear here, it seems to be possible to input chord symbols that show “C bass”, “C# bass” etc. via the Shift-Q popover, e.g. Shift-Q Cbass Enter. The hash appears to be correctly parsed, e.g. Shift-Q C#bass Enter, but the presence of a double b doesn’t work, so Bbbass, Ebbass, Abbass etc. can’t be used.

I think I’ve just solved my own problem - the German note names are parsed correctly - so I can use Bebass, Esbass and Asbass - but it’d be nice if the English versions worked too.