This is similar to what happens when you knit socks. When you are done with the W&T's and go to join it in the round, you will find holes in the spaces on each side where you've rejoined your yarn. The patterns don't tell you this. It's a little knitter's trick. Pick up a few stitches in this gap on each side. On the next round or two, decrease these stitches until you're back to your original stitch count. No more gaps.
Welsh corgis are cool.