BLK duplication variants

Some structural variants in gnomAD SVs v4.1.0 such as DUP_CHR8_77D3CCE7, DUP_CHR8_0DFC84AB, and DUP_CHR8_5D05B234 show detectable allele counts in the population data. However, the database also indicates homozygous individuals for the variants at an unexpectedly high frequency. Is there any proof of the homozygosity in the individuals with homozygous variants? Is the homozygosity assumed by the read depth only?