Missing decal vertexes in some cases

Hi guys, I’m new to ThreeJS and recently started using DecalGeometry to project some artworks onto clothes. The flow is that on the first click, I will be able to add an artwork onto a cloth, then I can move the artwork around by updating the decal with new geometry created from new mouse location. The issue is that part of the artwork is cut off at some point and I can’t figure out the reason why it’s doing so. If anyone has an idea what this issue is, please help. TIA.