Holes in Sith Commando model when in combat

[N-DReW25]

When a Sith Commando NPC attacks the player with a melee weapon, there is a noticeable gap underneath their armpits.

[DarthParametric]

The issue is that the bottom vert of the left armpit has a split ~50/50 collarbone/upper torso weight on the body mesh, whereas the equivalent vert on the left arm is 100% weighted to the collarbone. There's no issue on the right arm, as both equivalent verts are 100% weighted to the collarbone.

Edit: Seems like it's the left arm mesh that's actually at fault with the split weights, not the body mesh.