SURVIVOR always skipping 1 vcf file

[Anees-caas]

Hi, I am merging some vcf files command: SURVIVOR merge sample.list.txt 1000 2 1 1 0 30 merged_LR.O.2.vcf
#sample.list.txt
/home/ug1985/TEs/vcf/LR.O.vcf/ZGSP002.vcf
/home/ug1985/TEs/vcf/LR.O.vcf/ZGSP018.vcf
/home/ug1985/TEs/vcf/LR.O.vcf/ZGSP083.vcf
/home/ug1985/TEs/vcf/LR.O.vcf/ZGSP091.vcf
it runs successfully but the merged vcf only contains 3 samples instead of 4
#CHROM POS ID REF ALT QUAL FILTER INFO FORMAT SAMPLE SAMPLE_1 SAMPLE_2
#please guide me solve this issue