It must happen when you either switch from purl to knit or knit to purl, but not both. My only suggestion is to hold the needles as close together and really make sure the yarn is pulled snuggly as you do the first stitch of the block where the gap occurs.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry