Could the symbol of faith not have faith? (Talking Parsha - Vayeshev)

Yosef is the symbol of faith, so how could Rashi say Yosef received 2 more years in prison for putting his faith in the chief cupbearer?

Tuvia and Yitzi

Dec 11, 2020, 10:20 AM (GMT+2)

Could the symbol of faith not have faith?

Yosef is the symbol of faith, no matter what he goes through, no matter where or how distant from home ("God's name is always upon his lips").

So how could Rashi say Yosef receives 2 more years in prison for putting his faith in the chief cupbearer? How could the symbol of faith be accused of not having faith?