sandboxed tor browser crashing

I'm on ubuntu amd64 and had two crashes today, both using a freshly built sandboxed tor browser with the newest code. The first time launching resulted in immediate crashing:

2016/12/06  launch: Starting Tor Browser. 2016/12/06  launch: Complete. 2016/12/06  firefox: Gtk-Message: Failed to load module "gail" 2016/12/06  firefox: Gtk-Message: Failed to load module "atk-bridge" 2016/12/06  firefox: Gtk-Message: Failed to load module "canberra-gtk-module" 2016/12/06  firefox: Unable to update the static FcBlanks: 0x0600 2016/12/06  firefox: Unable to update the static FcBlanks: 0x0601 2016/12/06  firefox: Unable to update the static FcBlanks: 0x0602 2016/12/06  firefox: Unable to update the static FcBlanks: 0x0603 2016/12/06  firefox: Unable to update the static FcBlanks: 0x06dd 2016/12/06  firefox: Unable to update the static FcBlanks: 0x070f 2016/12/06  firefox: Unable to update the static FcBlanks: 0x2028 2016/12/06  firefox: Unable to update the static FcBlanks: 0x2029 2016/12/06  firefox: Unable to update the static FcBlanks: 0xfff9 2016/12/06  firefox: Unable to update the static FcBlanks: 0xfffa 2016/12/06  firefox: Unable to update the static FcBlanks: 0xfffb 2016/12/06  firefox: ![3] ###!!! ABORT: Request 130.3: BadShmSeg; 3 requests ago: file /home/debian/build/tor-browser/toolkit/xre/nsX11ErrorHandler.cpp, line 157 2016/12/06  firefox: ![3] ###!!! ABORT: Request 130.3: BadShmSeg; 3 requests ago: file /home/debian/build/tor-browser/toolkit/xre/nsX11ErrorHandler.cpp, line 157 2016/12/06  fatal error in the user interface: waitid: no child processes 2016/12/06  tor: Dec 06  [notice] Catching signal TERM, exiting cleanly.


Launching it again seemed to work but then playing a youtube video crashed the browser. It was a webm video using opus

firefox: ERROR: Failed to dlopen() libpulsecore.so: libspeexdsp.so.1: wrong ELF class: ELFCLASS32 2016/12/06  firefox: Redirecting call to abort() to mozalloc_abort 2016/12/06  fatal error in the user interface: waitid: no child processes 2016/12/06  tor: Dec 06  [notice] Catching signal TERM, exiting cleanly.