Terrain brush does'nt change

Hi. I´m a novel user of Unity, hoping that you can help me… When working on my terrain, something happened, so the brushstroke cannot be changed. I can choose the different options (brushes. settings etc.). but the same shape appears everytime I ad an mountain or hill (a steep, thin hill). I have tried to change all settings back to before this happened, but the shape cotinues to be the same. What have I done wrong?
With kind regards, Stefanie

I personally had this problem, but by default for some reason, when you use the terrain brush, the opacity is set to “0” maybe increase it to 100?

The opacity is set to 97, and all the other settings are as they were before the problem occured, so it seems to me, to be a bug or something? But I’m not sure.