These have been offered recently for sale as artefacts.
A warning has been added to the artefacts help scrolls
which I will repeat (in spirit) here as well, so there's
less chance of someone missing it:

These throwable/returning Javelins are something of an
experiment. They may be changed depending on our experience
with them. Please be sure that if you do purchase one, it
is still subject to change.

Just like when we change other things, if we change the
Javelins, we will not mess anybody over. If there is a
reduction in power, we will offer recompense, likely in
the form of a refund for those who want it.

Penned by my hand on the 10th of Aeguary, in the year 460 AF.