When trying to make a word as BOLD, the editor toolbar doesn't worked as intended.
I have experienced this several times by pressing the "B" icon button on the editor toolbar, however that didn't work either.
I guess you refer to your lastest answer and you tried to mark a word which is part of the quoted text?
In such case it indeed won't work, as you marked the text as code which means whatever you put there is shown as-is including the
This is by design of course and to "solve" it mark such text as quote instead then you can bold words.