[Closed] Undo of skinOps.addCrossSection crashes Max

the bug is very deep in c++ code. max crashes trying revert replaced references of envelope inner/outer controllers.
the same crash happens for any cross-section related skinops method. for example, copySelectedBone -> pasteToBone or pasteToAllBones.

so the best i found finally is to remove and add bone back.

(
	clearUndoBuffer()
	undo "Apply Skin" on (
		with redraw off (
			delete objects
			c = convertToMesh (cylinder())
			global __b = boneSys.createBone [0,0,0] [0,0,25] [0,0,1]

			select c
			addModifier c (skin())
			setCommandPanelTaskMode #modify

			skinOps.addBone c.skin __b 1
		)
	)
)
(
	skinops.copySelectedBone $.skin
	skinOps.removeBone $.skin 1
	skinOps.addBone $.skin __b 1
	undo off 
	(
		skinops.pasteToBone $.skin 1
		skinOps.addCrossSection $.skin 1 .5 1 1
	)
)