Difference between . and ./. for missing genotype in VCF created by GATK4 GenotypeGVCFs
What is the difference between . and ./. for a missing genotypes in a VCF file? For example in one VCF record I have these two sample genotypes.
GT:AD:DP:GQ:MMQ:PGT:PID:PL .:0,0:.:.:.:.:.:. ./.:0,0:0:.:.:.:.:0,0,0
The VCF record was produced with a recent version of GATK4 via GenotypeGVCFs.
The input GVCFs were created with GATK4 HaplotypeCaller.
The input samples are diploid.
There is no sex chromosome.
So it does not make sense to me that that . is for a haploid genotype and ./. for a diploid genotype.
Is there any meaning behind the different . and ./. genotypes? Or is this just somewhat random and do . and ./. mean the same?