You know what Iím gonna say.
I wanna hear......
OK, that griddle is not seasoned well. It may have been coated in veggie oil instead. I have never seen brown patches boil up like that and it's a bit concerning. I don't think I'd use it until I cleaned and seasoned it.
So clean it. I would start at the glass blasting cabinet, you start at the sink. Hot, hot water and detergent like Dawn. Strip it well, rinse and repeat.
Then put it on a big hot burner. If it smokes a little, proceed, but it shouldn't smoke a lot as oil should be stripped away from the cast iron. If it smokes too much, back to the sink until it's de-oiled, or outside and burn it away until it no longer smokes.
Once clean and hot, season it with lard and repeat until it's nice and black.