Intarsia blocks

I am currently working on the Knitting Bag sweater shown on the cover of the Sally Melville Color book. I have added the colors for the first blocks (on the knit side). And this was fine. However when I go to the purl side and pick up the color, something farkles and I get only half of the first stitch in the color and the other half in previous color. Can anyone suggest a reference for me to learn how to do this correctly?

I am an intermediate/advanced knitter, but this is confusing me. I do what has been defined as “combination knitting”. I know I am just missing something, but what?

Did you watch Amy’s video here? (scroll down) Maybe it will help?

When you change colors, the purl side always shows both colors. Some patterns use it as a design element, but looking at this pattern, it appears that the front is in st st, so I’m not sure where your problem is showing up?

I’m afraid I don’t know much about combination knitting, but when changing colors the knit side should always look like the picture in the book. :??