When does Petra "reset" to issue the final Boolean Gemini mission?

I have started collecting exotics in Destiny, on Xbox One. Some friends have told me that the Boolean Gemini is a handy scout rifle to have, and since I favor scout rifles the best, I have almost immediately started working towards unlocking it.

I found this page at prima guides, detailing the progression towards the rifle, in order to point me in the right direction.

I completed all of the Taken Champion missions from Petra, and had half expected the weapon to be rewarded at the end. Instead, Petra handed me over to Varik, where I completed a series of Fallen-related missions. I assumed that this was all part of the intended progression, and the prima guides appears to confirm that.

However, I have now completed all of Varik's missions, and not yet received my Boolean Gemini.

Making my way back on to the prima guide, I made my way to this excerpt;

Complete the remaining quests you can receive from Variks and that can be completed from the main system screen in the game.

With the first two quests down, wait until the reset for the following day, then you can gain access to the next quest. You get the Boolean Gemini Exotic Scout Rifle by completing the quest.

The guide states that Petra will reset daily, however, I have found reference to her resetting weekly. On top of that, the Destiny app currently has her resetting in just over 24 hours, implying she does not reset daily. I have seen other inconsistencies that suggest that this might have been pre-Taken King.

When does Petra "reset" to issue the final Boolean Gemini mission?