Unable to complete the "Marksman" challenge on Cuatro Colinas

[M]

Hello,
I've been unable to complete the "Marksman" challenge on Cuatro Colinas. I've killed male/female ibex well over 400m with single shots and it is not triggering the quest completion. I've checked the summary for each kill they report a distance of over 400m and killed in one shot. So I'm confused as to why it's not triggering the quest to complete. I mean this questline is already a grind.... Is this a bug or am I missing some parameter that isn't clearly called out in the quest?
I am using the 6.5mm rifle which is suitable for class 4-8 (which the ibex fall under at class 4)

[Pinger]

did that recently after restarting a new char a few months ago, it should complete if the harvest screen says its 400m+
Just be sure you are shooting an ibex and not the Mouflan by mistake as they share need zones if using the lake below the lookout point of Torre De Donna Emilia

[M]

I've shot Beceite ibex both male and female in single shots over 400m and that didn't trigger it either. I've verified on the harvest screen that the distance is over 400m. I imagine it just must be a bug. Shame, grinding for this Rayo skin for a few days now.

[M]

Update:
Tried same thing, literally changed nothing and now I get the challenge completed... Much confusion.