I'd need a lot of convincing it wasn't rather a bug in the simulator. An attainable amount of convincing, but it would be my first thought.

Why?

Bugs in code made it into space. These are documented.

Because the odds are that the simulator with which someone will run around yelling about the bug they found (which will get them links on HN and other fun perks) will have had less than 1% of the time spent on creating it than the code that was actually sent into space, and on the balance, given the observation of a defect in the combined simulator+Apollo code the highest probability locus is the new, untested code that was probably rushed out for publicity's sake and had no lives ever depend on it.

You seem to have misinterpreted my post as me saying I would never believe it was a bug in the Apollo code, despite me making very sure to explicitly disclaim that.

If it was anything remotely like the team handling the shuttle code[1], I doubt it.

[1]: http://www.fastcompany.com/magazine/06/writestuff.html

I would not take an even bet that there is any meaningful bugs in that code that NASA was not already aware of.

Here's a nice detailed study of the 1201/1202 alarm that caused the AGC to reboot while Apollo 11 was landing:

http://www.hq.nasa.gov/alsj/a11/a11.1201-pa.html