Well, any time you see something unusual in a pattern, I guess you could look carefully at whether it's right. I'd be looking at the picture to see what the yos are doing just out of curiosity, I like understanding how the pattern works and what different stitches are doing before I start.
I can't really suggest that this is definitely right, but some patterns do have a yo at the start or end of a row, so the fact that it's there doesn't automatically mean there's a mistake in the pattern and a subsequent knit stitch forgotten. Especially in lace, funny yo-type stitches aren't unusual.
I agree that the pattern should be specifying how to decrease.
If you are finding the yo especially difficult, I'd have a look at what they do in the pattern. If it's something you feel can be dispensed with, you might prefer to do another increase instead (assuming the yo is retained in later rows).
Stitch count is one of the easiest ways to detect a mistake in pattern instructions so well done.
If you have further questions, a pic or link will help us advise you on yo and decreases.