In Apple Podcasts, ratings and reviews are not the same. You can leave a star-rating without writing a review, but every written review must include a star-rating.
If you look at the reviews tab for your podcast in the iTunes store, you'll see the two separate numbers: a number of ratings (left and center) and a separate number of “customer reviews” (right). It's common to see more ratings than reviews. That means some of the people who left a star-rating did not include a written review with it.
My Podcast Reviews shows your review data. Thus, My Podcast Reviews is reporting the number of reviews correctly.