I "fixed" Find prime number between 1 to 1000000 - it was an open spoiler+code tag in BrowserUk's post that got truncated once it got written to the DB and then read back. While the node remained in the node cache, it wasn't truncated, after the DB roundtrip it was. The rendering code there needs to become more robust. It likely dove into a long backtracking regex where it should have quit.