Harsh outline around brush strokes?

Hello, I use the brush tool in order to redraw certain parts of layers. Suddenly, new brush strokes have this problem that I can only describe as having rings around them or just a harsh outline around the brush strokes. This seemingly only happens when using a soft brush, and is more noticeable if you repeatedly use the brush in the same spot. However, this harsh outline can still appear even if I am just circling the brush tool around the layer. I am wondering if this is because I am using the brush tool in the same spot again and again. Any tips on fixing my problem?
