My brother and I both share 26.19% DNA with my grandfather. Huh?

My brother, paternal grandfather and I each have 23andMe profiles. According to our results, my brother and I both share 26.19% of our DNA with our grandfather across 21 segments.

My understanding of recombination is that we're statistically likely to inherit different proportions of DNA from each grandparent. Chances are slim that the exact proportion inherited from one specific grandparent would match between non-identical siblings. So what's going on with us?