@kinokatsu,
You can add dummy stripline with transparent color and position it below the actual stripline as shown in this JSFiddle.
In order to help us in understanding the issue, please have a reproducible demo of your chart.
This one step can assure you a speedy response. Fork out our template JSFiddle and reproduce the chart at your end. Try to keep it to the bare minimum by removing unnecessary code.
From what we have observed, sometimes things get delayed mostly when we are not able to reproduce the issue or not able to understand the exact requirements or the solution that we provide may not work properly due to the variation in chart-options being used by you and us.
Having a JSFiddle helps us in figuring out the issue and many a times we can just edit your code on JSFiddle to fix the issue right-away.
—
Vishwas R
Team CanvasJS