so I had a city for the broken lords and it gets taken over by the necrophages, I had 8 population, then when I conquered it back all of the workers were in the food area, and well as most know broken lords don't use food, so am I shit out of luck and the city will only have workers there or is there something I can do to fix that?

I confirm this bug. I had that problem when I captured a Wild Walkers city (not being able to drag workers in the food production into another production type)

Workaround : In the city screen, you can select a preset (Food, Prod,...). Select the production one, you'll have all your workers.