About Assembly Features in Part
Assembly features that intersect parts can be set as visible at the part level. When set such, the feature is considered to be a part feature as well. Suppressing an assembly feature in Part mode, does not affect it in the parent assembly. Deleting the feature in Part mode removes the intersection in the part at the assembly level. You can modify the dimensions of the parent feature in Part mode provided the parent assembly is in session. Regeneration only updates the current part. To update other parts intersected by the feature, regenerate them individually or regenerate the assembly. Features in an intersected part should not directly or indirectly reference an assembly cut.