DumpSTR: Without --drop-filter, the output shows HET=-1 locus

[Paddy1401]

[Paddy1401]

dumpSTR --vcf input.vcf --out output --min-locus-het 0 --max-locus-het 0.9. This is the command I used, if I don't use --drop-filter option. The output file contain locus that have HET= -1. Did I make something wrong since from my understand the heteroyzgosity can not be negative. Moreover, I also face issue where the same locus position (i.e.. 12xxxxx) is duplicate or triplicate in the output file