This is indeed a long-standing bug with Chrome:
https://code.google.com/p/chromium/issues/detail?id=45986
This bug was first reported in v.5 and currently scheduled to be fixed in v.19 (unless it gets bumped back again); current v. is 17, but it's become a more prevalent problem lately as Chrome gains in popularity.
Unfortunately, it appears to be the act of redirection itself, and the specific way PayPal performs that, which trips over the bug in Chrome, so it doesn't matter what URL is being redirected to after checkout; affected buyers aren't even getting as far as hitting anything at our end before Chrome hangs.
Right now we're looking into the feasibility of possibly detecting when a buyer is using Chrome before we send their cart order to checkout, so we can at least remove the return URL from their order details and maybe squeeze a message into the Complete Purchase button that PayPal shows after checkout, advising the buyer to watch their email for further details about their order.