Recently it seems PDF file open gibberishly. However, closing them and reopening them gets them back to normal. OPening them on other computers does not do this - but on my computer both Acrobat and Preview yields the same.
i dont know much about pdfs but could it have something to do with text encoding? that looks like what happens when you're using the wrong thingy like iso-8859-1 or whatever in a web browser.