OK, I hope I explain this where you understand if not please let me know.

This bug is occuring on the test server.

this bug can be recreated quite easilly.

1. chop down a tree,
2. chop into large logs or small logs.
3. Exit game log into another character at the same location.

The tree will be back in choped down position . So you can then chop it back into large or small logs. The prior large or small logs remain.

While this is handy for experimenting on stacking logs, I think all can see issue of this duping bug. :P

edit

anymore information needed please let me know more happy try stuff =).