2.8.0 \flat in quotes

[Paul Scott]

\version "2.8.0"

This doesn't work:

{ c''1^\markup{ "B \flat" } }

These work:

{ c''1^\markup{ B \flat } }

{ c''1^\markup{ \line{ B \flat } } }

I needed something to work in \column.  I first tried the quotes which 
didn't work and then \line which did.  I would prefer the quotes to 
work.  Is this a bug?

Thanks,

Paul Scott