If using OnComponentFracture in a blueprint and the DM has debris enabled with debris timeout and/or crumble smallest chunks when the debris is removed it causes OnComponentFracture to fire for each chunk it is removing.
I discovered this when using it to spawn an actor. So instead of getting 1 actor, a DM with 100 chunks would give me 101 actors.
I solved this with DoOnce. But, I still feel that the chunks being removed should not fire OnComponentFracture so I am submitting this as a bug report.