Try to remember that this is annually a "different" week in North American Trading.
We go from one Monday with a Canadian Holiday through to the next Monday with an American holiday. Many of the really big players take this week off to get things started for the summer.
My broker for instance will often work from home this week for that very reason.
We have had very thin volumes which allows for lots of "experimentation" should some person or persons elect to try something.
By about next Wednesday we should be settling in for the last big push before true summer doldrums.
Onwards and Upwards.