Green Circle on Thralls

What does the green circle on some T4 thralls mean?

Do you by any chance use one of Multigun’s thrall mods? I believe those green circles indicate “bonus” thralls that aren’t in the official game.

Yes, it should be so. I use one of those mods as well and get some t4 thralls with the circle.

Aha! Yes I do. Thanks for the info.