Ok purple steel dagger is an interesting one.
My alt picked up a purple steel dagger just prior to that from a grave.
Later what I bored and checking the logs, a spammed message appeared from the trading post saying it could not create an item.
A bit of investigation showed that the said item was in fact your purple dagger which has expired and was trying to be put back into your inventory.
However, a Purple dagger is a unique and in fact I had the dagger on my alt and so the create kept failing.
More investigation revealed that the test for uniqueness did not include items placed in the trading post and so a new one spontaneously appeared which I happened to find. Once I had it, the expired trade could not be created as it was unique.
I had to destroy your item to stop the perma spam.
It was a while ago but I thought I gave my dagger to you, given that technically you had it first.
I have also modified the unique rules to check the trading post.
If it was not returned then let me know.