I've been informed that this is intended. Yes the workshop is not producing income but it is working as intended. It is producing daily and trying to increase the capital. Workshops are giving %20 of their capital to player when the capital is > 10000. Both brevery workshops are below 10000 capital so they are running on their own, not giving the money to the player. Once we go to the related towns and buy all the beer, we can see that they sell their products in profit and give their leftover money to player. So everything seems to be intended.