curve~ bug?

I don't know if curve~ has always done this, but if I send a list defining the attack and decay portion of an envelope, and then send a message for the release portion *before* the attack slope has completed, the decay message isn't cleared, so the decay happens after the release. Is there some way to clear the messages held in curve~ that haven't been processed yet, or is this a bug?

you can see in this example that when you trigger the release before the decay kicks in, line~ works as expected while curve~ doesn't clear the decay message, and rises to the sustain level