It’s an error in the pattern. Here’s a way to do it.
K1, k2tog (raglan edge), knit to end of row. Turn, bind off 5sts (neck edge), purl to end of row.
Then follow the directions for decreases at the neck and raglan as written.
This makes sense with the directions for the right front. Yes, it’s offset by one row from the right front but that’s common in sweater patterns. It’s only a fraction of an inch and won’t show.