Why do some of your vcf genotype files have genotypes of ./. in them?

Our august call set represents a  merge of various different independent call sets. Not all the call sets in the merge had genotypes associated with them, as this merge was carried out using a predefined rules which has led to individuals or whole variant sites having no genotype and this is described as ./. in vcf 4.0. In our november call set all sites have genotypes for all individuals for chr1-22 and X.