Dram and Bitcoin signs show as missing character boxes in 9.1 What is a Commodity?

[colindean]

[colindean]

This happens because the version of Source Serif Pro font that I have doesn't have these characters, as indicated by build output I've ignored until now:

[WARNING] Missing character: There is no ֏ (U+058F) in font [SourceSerifPro-Regular.otf]/OT:script
[WARNING] Missing character: There is no ₿ (U+20BF) in font [SourceSerifPro-Regular.otf]/OT:script