StrainGR identifies SNVs in samples where StrainGST did not detect a strain

[kebow]

I have sets of samples belonging to different individuals and am comparing the output of StrainGST and StrainGR. I've come across cases where StrainGR has called SNVs in a particular sample that StrainGST did not detect a strain of the relevant species in. Is this to be expected where strains of a species have been detected in some samples from an individual but not all? Is there any advice on interpreting this type of situation?

Thanks