Skilling, killing and doing things that make you gain xp in general, generate this stackable object named 'Enchanted Snow'. For some reason, and I think this is client-sided, because I get a pop-up warning from my task bar when this happens, the client destroys this. There's no sound reason why any person would do this, so this looks very bot-like.
It's part of the unexpected item handler because it's something that many scripts bots wouldn't know how to react to. If a script bot is trying to drop the entire inventory, and then this object appears which it is unable to drop there is a chance that the script bot would continue to try to interact and drop this object for hours. By destroying it we minimize the impact of these objects. This is similar to how it destroys strange and golden rocks.
I am once again undecided on this issue. I need more reason to convince me to change it in the next release after all. Although the snow may be useful, it's also something that could make scripts bots that aren't prepared for it get stuck and that could become a big issue.
If you are going have the client let the snow be can you do the same for the strange rocks? They are used in getting kudos for a quest. Or I guess you could probably add a boolean into the user accounts defining whether to destroy the rocks or keep them.
For now I've decided to destroy them all but Arbiter is planning on adding an option under settings to allow you to customize what is destroyed.
