Stroke tool not working when a drawing has a fill

My partner, who is using the same exact version and doing the same exact things I am doing has no problems like this what so ever.

I’ll draw a picture with a brush, then fill in everything with color. I then attempt to shade using the stroke tool but it ignore every line I have besides the outside lines, making it impossible to shade with a fill.

It works just fine with the lineart alone but doing it this way mean if I need to edit any of the shading, I have to delete all the filled areas and redo it all.

My partner and I cannot figure out why it’s not working right.

I can’t tell what’s going on in your images but if your stroke is not separating regions it’s usually due to that region not being entirely closed. Zom-in and have a look if there are gaps.