So you don't know if it's an exchange bug actually.
Also, it's limit to spears? has no sense.
I saw this message in a lot of packets, just having an "unexisting/not near" ID and could be triggered.
Since all my accounts slots are busy at SRLatino, I have to test at another one. This is what I got.
A tool doing that when sending any skill, it's easy actually. But because exploit behavior will be useless/patched at the end.