So, I'm rigging a model and I noticed a problem with the Arm. As shown in the pictures, the upper part of the arm collapses on itself when I move it. The rest of the arm is fine.
I'm still learning how to properly rig and such, so if anyone can tell me why this is happening, that would be greatly appreciated.
Here is the Blend file, i managed to get the head and somewhat of the left arm and still kind of new to rigging so it's not the best. I'm rigging it for vrchat so. https://drive.google.com/file/d/12SQNEksYcoQCIxSNnqGwRWLvLGupZK4y/view?usp=sharing