I think
this is the pattern.
The number of sts and a single inc at each marker don't add up for me. Each round is to inc 8 sts, there are 4 markers w/ 1 inc ea. The cast on is 66 sts, then:
" Rnd 1: (k1, m1L, k to 2 sts before marker, m1R, k1, sm) repeat around. (74 sts)
Rnd 2: Knit all.
Rnd 3: Repeat Rnd 1 (increase rnd). (82 sts) (You should be able to switch to the 16” circular on this row.)
Rnd 4: Knit all.
Rnd 5: Repeat Rnd 1 (increase rnd). (90 sts)"
The way I'm reading it, you need a double inc at ea marker to obtain the stitch count indicated.