Self striping yarn isn’t striping evenly?

So i’ve been knitting a scarf as my first project using the knit stitch. it was going well and i’m using a Carron cotton Cakes self striping yarn. the yarn has been going about 25 rows before switching to a new color, but now one of the colors (purple) is going over 25. I’m already up to 30 rows in this color and i still have a lot of yarn left before it switches to the next color. Is this possibly a manufacturing error? if i was knitting something small it probably wouldn’t be so noticeable but since it’s a thick scarf it’s pretty obvious that the purple is longer than the other colors :( i estimate it’ll hit at least 38 rows before it switches to the next color

edit: the color is amethyst sky by carron cakes. the purple row ended up being 48 rows and the following color (blue) went back to around 25 rows. so weird.