More on that equal weight underperformance thingy:

$SPX gains 2% or more for the week and $SPXEW lags by -0.50% or worse (ytbd into today's close)

Only weeks that match:

7/13/2015
11/26/2018
10/13/2008
10/19/2015
9/10/2007
5/7/2018
3/17/2008

Some ominous weeks here...