I'm pretty sure telling a clone to make another non-existent clone and then telling the non-existent clone clone would mess up the scripts (Just like 0/0 on a calculator).
Technically it's not the clone making a clone of itself, but rather some third party making a clone of it.
Even so, I'd agree it shouldn't happen. But then I wouldn't have that pulldown menu in the block; it'd just be A CLONE OF MYSELF and if a third party wanted to clone me it'd use TELL same as for any other meddling. But alas, Jens just copied the Scratch blocks.
The reason there's such a thing as a dead clone is that sprites are first class, so your program might have a list of sprites, made before the clone was deleted, that still includes it. So it does exist, as long as something points to it.
But yes, it would be better not to allow cloning it. But this is a low priority thing to change, I think.
OK. But I still don't understand why the clone of the non-existent clone is deleted (by reporters) but exists (scripts work and you can see it in the stage)
The [scratchblocks](a new clone of[ v]::control[/scratchblocks] block creates a clone of the sprite in the dropdown, no matter where you call it from. Same with the command block.