Kirac Mission No Shaper Guardians

I've cycled through about 50 missions, plus whatever I've done before blowing through my scouting reports. So far, I've noticed I do get a frequent amount of Elder guardian maps, however, I've gotten no Shaper guardian maps. I do get a lot of maps that have shaper influence, however, they don't have the guardian, e.g. Maze of the Minotaur, etc.

This seems very unbalanced and might be a bug.

I think Elder / Conq boss maps are just more common than shaper ones.
Are you using Influenced reports?
I did find that I got shaper guardian maps less than the others, but for EGG and stuff I always wanted more conq maps since they were much harder to grind for compared to Elder / Shaper maps.