Brush keeps changing config

Hi community,

I have been using AI for a long time and I have never had this problem before: once I prepare my brush with colors and configure I need to get filled the draw, I start making.

For example I start to make a circle and it supposed to be filled with the color I chose before, but I doesn't, automatically brush changes to only lines and gets no fill on it, all I get is an outline circle.

What do I have to do? I can't change it.