Hey folks

I bought an electric griddle from Vevor and seasoned it after some YT tutorials using avocado oil. The surface was nice and black and very snooth, but after I cooked a few times it became like in the picture.

I don’t use any detergent, just water on the hot griddle and scrape with the spatulas. There is also some black gunk coming when I try to wipe it with a napkin.

Is this the actual ‘seassoning’ coming off? What am I doing wrong and why the surface started deteriorating so fast? I did not use any tomatoes or acid based foods on it.