Rapid Assault Spearheads Cannot Apply More Than One Poison When Detonated

I've done a few testing attempts on this and I'm pretty positive that if you detonate multiple RA spearheads on a target it will only ever apply 1 poison. As far as I am aware each spearhead should be a separate instance of damage and therefore apply its own poison if I have increased limit but even as pathfinder whenever I detonate 2 or 3 or 4 spears its always applies a single poison.

It would make sense if all the spearheads added together for the sake of bleed and poison but as far as I am aware that is not the case.

This could be a really cool unique pathfinder build if it was working as intended