The great Shift occurred between 2010-2015. This was the window in which it was possible to make the greatest changes, to shift the path humanity had been on towards a new Golden Age instead of towards destruction. In this time, Kirael doAni has done most of his great work, and made most of the changes that are now resulting in the mandala effect.
People first started noticing mandala effects in 2010, but it has not become widespread until late 2015. It is not a coincidence that these are exactly the Shift dates. Something around 2010 changed so that people could start noticing, and around 2015 the changes became bigger and people more aware.
The Shift was an extremely important time in human history. While the window was open, it had to remain a fixed point in time, and any timestream had to go through the key energy events that occurred during this period.