Curse me for presenting myself as someone having interesting secret knowledge. Now I get several PMs asking for details.

In short, this "incident" was about one or two SIAI folks making a couple of obvious errors of judgment, and in the case of the error that sparked the whole thing, getting heatedly defensive about it for a moment. Other SIAI folks however recognized the obvious mistakes as such, so the issue was resolved, even though unprofessional conduct was observed for a moment.

The actual mistakes were rather minor, nothing dramatic. The surprising thing was that heated defensiveness took place on the way to those mistakes getting corrected.

(And since Eliezer is the SIAI guy most often accused of arrogance, I'll additionally state that here that is not the case. Eliezer was very professional in the email exchange in question.)