I have a rig setup with 4 Slots for Bounding Boxes.
Within those bounding box slots, there are 4-6 different bounding box entries.
No problem with that. They all show up in the inspector.
However, there is something strange. They are indenting oddly:

Maybe this belongs in the Bug forum?
Either way, I believe its related to this:
foreach(var entry in boundingBoxTable){
EditorGUI.indentLevel++;
EditorGUILayout.LabelField(entry.Key.Data.Name);
EditorGUI.indentLevel++;
The indent level is not reset between entries.
I fixed it by adding this at the end of the loop.
EditorGUI.indentLevel
---
;
EditorGUI.indentLevel
---
;