Unexpected value in GT filed called by isaac variant caller

[sasasa123456]

Hi, there.
I'm user of Isaac aligner and isaac variant caller.
I realigned Hiseq reads by Isaac aligner and then called variant by isaac variant caller with following commands.

isaac-align -r /path to/iSAACIndex.hs37d5/sorted-reference.xml --base-calls-format fastq-gz -b /path to/Run_01 -o /path to/sample001/ -t /tmp -j 30 -m 120

configureWorkflow.pl
--bam=/path to/sorted.bam
--ref=/path to/hs37d5.fa
--config=/path to/isaac_variant_caller-v1.0.6/etc/ivc_config_default.ini
--output-dir=/path to/isaac_variant_caller/;

make -j 40 -C /path to/isaac_variant_caller/ 1> log 2> err;

As a result, I got sorted.genome.vcf.gz file.
In this file, I found unexpected value "1" in GT field as follows,

22 22536804 . T C 207.0 PASS SNVSB=-24.6;SNVHPOL=2;SNP;HOM;VARTYPE=SNP GT:GQ:GQX:DP:DPF:AD 1:33:33:12:1:0,12
22 23568516 . T A 331.0 PASS SNVSB=-34.0;SNVHPOL=3;SNP;HOM;VARTYPE=SNP GT:GQ:GQX:DP:DPF:AD 1:66:66:23:3:0,23
22 27436971 . T A 224.0 PASS SNVSB=-28.9;SNVHPOL=6;SNP;HOM;VARTYPE=SNP GT:GQ:GQX:DP:DPF:AD 1:36:36:13:1:0,13

I expected these GT value should be "1/1" because of AD value.

I counted these unexpected value in gVCF file as follows.
zcat sorted.genome.vcf.gz | grep -v "^#" | awk '{print $10}'|awk -F: '{print $1}' | sort | uniq -c
866614 .
248249 0
394681299 0/0
2662537 0/1
3021 1
1871600 1/1
21859 1/2

Although "." would be derived from gVCF annotation, I found 3021 "1" value in GT field.
VCF-merge by VCFtools was failed by this unexpected value with the extracted VCF files from these gVCF files.

I would like to know why these unexpected values are existed in my files.
Does Someone know answer for this unexpected value ?

isaac version
isaac_aligner-01.15.02.08
isaac_variant_caller-v1.0.6

[hguturu]

I noticed these types of issues in a batch of variant calls I received from Illumina as well.
It is tagged with
##source=IsaacVariantCaller
##source_version=starka-2.1.4.2
Is there any idea what is causing the caller to call hemizygous variant calls on autosomes?