While we generate matches for BrandMatch every two weeks, the nature of that report means that there is a fair chance for any brand in the network to not receive a BrandMatch report in a cycle. Because it's based on both overlap in shoppers and other possible matches for a brand there are possible competing match options that require the system to leave some brands out for a cycle.
It's not uncommon for a brand to only receive new brand matches occasionally, and in some small number of cases, not at all. The conditions for these matches evolve with time as the network grows and brands available change, same for shopper overlap between brands.