I thought this was just me but have heard others having it happen too and it seems to be happening more often now and didn’t see a post.
Sometimes, it seems completely random Primarch hunt power gets set to 0. I’ve had it happen right after entering Atlas trying to make my first attack and also in the middle of gold hunting, doing runs then all of a sudden I get hunt power is not high enough, check the primarch details and it’s hunt power is 0.
This can be fixed by exiting Atlas and going back in. Sometimes I need to do it more than once to get the primarch’s hunt power back to normal.