I reproduce the issue on 1.60 and 1.70.1 on MBP early 2012 with MacOSX 10.8.2
I managed to get sub back by unticking ASS/SSA subtitle styling (emptying Audio / ST priority didn't work, clearing Forced sub field didn't work either). To be honnest, I haven't tried any combination of these settings, all I know is that styling off + the other 2 fields empty make it work)
I also tried to build 1.71 from sources, the build succeed but there is no DMG produced, and the App that is available doesn't work (it doesn't launch)
At the end of the build, there is an error in the XML app template, saying that $APP_PACKAGE is not a valid reference.
Someone here had the issue : viewtopic.php?f=14&t=14455
. I tried to chmod a+x the.app, it did't work either.
So I'm left with a workable solution, but I can't wait to have 1.71 (since I cannot build it myself)
Anyway, thanks for your efforts guys !