This is a copy paste of a help request we sent to the discord but got no answer, my boyfriend is trying to figure it out and I don't personally use Krita so I'm not really sure how to fix it, if anyone knows anything please let me know.
"it shows up when i export it as a png as well. it cant be seen when i zoom in in krita. the second image shows that the outline can be erased with the eraser tool, but i dont want to have to go around every single line i draw to erase it. ive seen a couple posts about this issue but not many replies and the replies they have haven't been helpful. one being to select opaque, invert selection, grow by a couple pixels, and delete. this does get rid of the grey, but only if i grow by 3+ pixels. but this makes my lines much smaller, especially when using a smaller canvas. so im hoping that theres another solution. also this is only an issue on a transparent background. the grey outline doesn't show if im drawing on another colour"