This is a weird bug and I don't know if I accidentally tweaked a setting one day and don't know how to fix it. It's been like this for about two months and it's partly why I took a break from drawing. When I'm drawing, it doesn't matter what brush (marker, pencil, pen, brush, anything) or eraser I'm using but when I need to change between the two, it used to be that it would automatically toggle between the color I'm using and transparent (for the eraser). Now it doesn't. I have to manually select the color or transparent when I switch tools or else I will erase with color or draw transparently. I don't know what setting I messed with or how to fix it so I can swap my tools without also manually changing my color input as well.
The attached image shows where I have to manually toggle color and transparency.