This is a text encoding problem; the weird characters are your system's attempts to present, in those cases, apostrophes. Dashes, smart (curly) quotation marks, and ellipses may also show up that way. I doubt it has anything to do with format=light or style=mine, unless you have a text encoding defined in your style or something. I don't know enough about what's going on under the hood to explain it, let alone fix it, but I can say that every now and then I open a journal page that shows such things, and changing the text encoding (in my browser, Camino, it's in the View menu) will fix it; usually I change it to UTF-8, but rarely that doesn't work and I have to try others at random. So fiddle around with text encodings and see what happens!