Some Monster Life's Inquiries

Anyone knows how does the monster release system work?

When you release a monster, there is a small announcement indicating where is the monster being released right?

Is it being released in your world, in the channel where you are playing ML in or randomly?

I want to know this because one of the achievements requires me to find the monster I had released. (I would like to know how does this system work actually)

It's not necessarily in your world. I've gone to check on the farms of people who've caught my monsters, and see they are from all worlds.

It follows that it's not necessarily on your channel if it is in your world. And I have no idea whether the location they say is in any way related to the location it actually goes.
That achievement seems to be entirely luck-based and very, very rare.