How often do the "Questions to the Producer" events happen?

Not long after HW came out, there was a really neat 'Ask the Producer' event going on in the forums. A lot of the questions were based around the new classes, and Yoshi-P essentially saying "LOL git gud". But that made me wonder...does anyone know how often these Ask the Producer type things happen?

Usually before major patches and content updates.

I'm asking where is my giant egis

Sometimes I feel like they only "answer" questions they were planning to divulge information on anyway. :-/