Well, somebody was careless & didn’t notice that the pattern didn’t call for 3” of ribbing all around. And I do like the look of the mitts done correctly. Another time. This time, I will recover by doing 15 rounds of ribbing, then 10 rounds of ribbing on half the stitches before the thumb gusset. I added a stitch so I was back to 50, then did 10 rounds of rib/SS & 8 rounds of ribbing. Thumb as written.

Note for next pair - patterned yarn obscures the ribbing detail.