\textbf does not work

[seisure]

Bold text with \textbf does not work. The following error occurs.

Font shape T1/lmr/bc/n' undefined. using T1/lmr/m/n' instead.

I could tackle it down to be a problem with the "Customizing GanttChart" section in the preamble.tex. There is the bfdefault command redefined. When commenting this line out, \textbf does work without a hassle.

\renewcommand\bfdefault{bc}

I opened this issue, because I don't know why this was introduced in the template and without understanding the intention I don't want to change it. Could the initial author check this please?

It's not part of the thesis layout, why \textbf did work there from the beginning.

Thank you.