Hi, This Heisenbug was arduous to nail down. The following code causes the stack overflow on the first run: http://pastebin.com/raw.php?i=qwGGBrJf If the file is changed to compile successfully, then the compile will succeed on subsequent attempts, even if the changes are reverted to the original state. It only breaks on the first try. Something must be cached, but I don't know what. $ context --version mtx-context | current version: 2014.10.07 11:14 $ luatex --version This is LuaTeX, Version beta-0.79.1 (TeX Live 2014/dev) (rev 4972) $ uname -a Linux 3.13.0-36-generic #63-Ubuntu SMP Wed Sep 3 21:30:07 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux There might be some extraneous bits, but hopefully that will be enough of a clue as to the problem.