More specifically: I've recently learned that using a consumable item (pickle, candy, spell stones etc.) after receiving it from someone causes the line referring to the transfer of that item to vanish.

 

My personal opinion is that it defeats the purpose of the trade log, as it is.

 

Is it intended this way, or bugged?

As I said in chat:

 

I'd make a guess that this is "meant" to happen but not "desirable". 

 

What I mean:

 

I'd assume that once the item is consumed, it is wiped from the database - along with any information with it, as it is 'no longer required'. The trade logs probably search by item ID. As there is no ID, it has nothing to search for.

 

If it were to search by ID - or something else specific to that item - then yes, it's doing it's job right. The fact it doesn't store the information afterwards is the annoying part.

How I come by this assumption:

 

The same thing happens when converting creatures to totems; their creature logs vanish. But they then appear in the items list. Why? Probably because the logs search for these things by ID. So when the creature was converted it gained an item ID rather than a Creature ID.

 

I could, however, be completely wrong. So feel free to add any other ideas. :)

While guesses about how the system works are amusing, they are in the end pretty futile and can end up spreading misinformation. So personally I would discourage guessing and telling people these guesses.

 

Simply put, when the system was set up (PC - Pre-Chew) the tradelogs were stored with the items and means that on using these tradelogs are lost. There is a plan for a system which would change this, and make the tradelogs much more useful (and less likely to break) but this involves converting over a large amount of data, or writing a hack between the current systems. So its all planned out, I just havent decided when I will eventually implement it. Since there are a lot of things vying for my time I dont know when this will get done, but its all planned out and noted down.

 

So, it works like that yes, its not that great, but thats how it is.