When editing exclusions or inclusions with a repeating rule, or when deleting an entire event, event instance nodes that are in the past (earlier than the current date) are not removed or affected, even though the repeating rule thinks the nodes have been removed (they sometimes disappear from the rule entirely).

I've changed the rule to "delete all instances" not just "future instances," but this seems to have no effect. Only future instances are properly removed or deleted.