Would straightening the fabric of the offending strips do the trick?
Once upon a time many, many years ago public schools had home economics classes for girls (some very enlightened ones had classes for boys too). In one of those classes I learned about fabric that was printed off grain and straightening fabric that had been pulled off grain somehow. The teacher told us not to use fabric printed off grain for projects that had to "fall" correctly. If you cut according to the print, the project was askew. If you straightened the fabric, the print was askew. Bottom line there was check to see if the fabric was printed off line and avoid it if possible. The next most important thing she taught me was how to straighten fabric.
She advised us to find a friend who sewed and would bring a feel for fabric to the straightening project. That friend would "girl" (not "man" - teacher was early women's libber) one non-selvage edge of pre-washed fabric, a corner in each hand. You would take the other non-selvage edge and its corners. The fabric would be gently "tugged" or pulled, catty corner, diagonal by diagonal, until it was straightened.
It seems the washing and straightening would do the trick for the offending strips.
Hugs, Pat