Unfortunately, as of the information available, the BoundingBoxFollower component in spine-unity does not support tracking vertex deformation animation of BoundingBoxAttachments. It only generates them once at the start and tracks which BoundingBoxAttachment is enabled at a Slot at the current frame of the animation. This means that any deformations made to the bounding box in the Spine Editor will not be reflected in Unity at runtime. Additionally, it's mentioned that updating the vertices of moving colliders every frame would be costly for the physics engine, and using rectangular bounding shapes for moving objects is generally recommended over mesh- or polygon colliders.
