Strelka2 stomatic calls, where is the GT tag ?

Question

[simplitia]

Hi, I'm using Strelka2 with for exome sequencing for somatic calls. However when I use annovar it crashed with a warning that GT tag is not present. What is strange is that I've seen other post with Strelka output with GT tag. I'm confused, where is the GT tag and can I add this to the vff so that I can get annovar to work?

thanks! A