Differences - AttachToComponent in Construction Script vs 'drag-drop' attach in Components Tab

Can anyone explain the differences between;

  1. Attaching a static mesh to a component using “AttachToComponent” in the construction script of a blueprint (the SM exists in the level).

and

  1. Drag-dropping a SM in to the “Components Tab” to attach it to a component?

The issue I’ve run in to is that overlaps aren’t been triggered using “AttachToComponent”, but they are when drag-dropping.

This is using the BP_MotionController blueprint, Motioncontroller as the component to attach to, and a simple SM. The instanced SMs were set up with identical properties. The SM in the level required checking “Generate Overlap Events”. Curiously, “Generate Overlap Events” was already checked, and “Collision Preset” set to “BlockAllDynamic” after drag-dropping to the Components Tab as if inheriting from a parent.

Been stumbling over this for a while. Any help appreciated!