Errata is no longer available from the publisher, but a helpful knitter offered these notes:

Toe Round 1: “{K1 make 1 left (M1L), knit to last stitch on needle, make 1 right (M1R), k2} twice” should be “{K1 make 1 left (M1L), knit to last stitch on needle, make 1 right (M1R), k1} twice” otherwise the end of round bleeds over into the next round.

Heel construction/colorwork issue: the start of the heel turn leaves the active colorwork yarn at the opposite edge of the sock from the BOR, but the end of heel flap leaves you at the BOR. To resume the foot pattern with yarns together, work the back half of the joining round in colorwork.