I've seen this issue before! Do you have an intel graphics card? Somebody else had this issue, and we tried to figure it out. Turns out, it was an issue with the Intel Graphics driver. You can see more details about the issue here when I reported it to the Love2D issues page: https://bitbucket.org/rude/love/issues/1199/stenci...
Try getting the latest graphics drivers. If that doesn't help, then I'm not sure what would fix it.