Need help with a result from Analytics

Hi all,

We are in the process of building a widget with these criteria:

Visualization: Line Chart

X-axis: order weeks since onsale

Values: Running sum of # of unique package seat key

Break by: last 5 seasons

The result looks like this:

 

Do you know why the X axis jumps from 102 to 394? Please advise.

Best,

Tom Nguyen