Joining colors

Hi,
I just started knitting again after 20 some years. I am making a scarf using the garter stitch. WhenI tried to add a different color, one side shows a clean straight line of the different color, but the opposite side shows one line of the contrasting color under the master color. Am I doing something wrong or maybe this can’t be avoided with the garter stitch?
:wall:

I don’t think this can be avoided with garter stitch. :frowning:

Yup…Ill agree.

It’s known as the dreaded purl bump (according to Elizabeth Zimmerman.)