Every item i buy remain in the next snapshot. Anyone could check it.
Here an example:
https://theunderminejournal.com/#eu/gordunni/item/74611
EU median price 50k, but it listed for 150g whole day.
I think the question here is: what is the intention for the “quantity” field in the auctions (of stackable items). Currently it seems to be the initial amount of items in the auction, and never changes. I would have expected that as parts of auctions sell (which is now possible since the 8.3.0 AH), that the quantity (and remaining buyout) fields would get lower over time (when comparing multiple scans that contain the same auction).
@Araspir: can you clarify what the intention is: what should be changing in consecutive scans for an auction that was partially sold? It would be fantastic if an auction partially selling would be actually visible in the AH dumps, since that is proof something was actually sold, and not a canceled auction. However, as mentioned, currently the “quantity” field of auctions never changes.
Can confirm for Burning Legion and Draenor EU that false Auction Weeds auctions have disappeared 
Sorry to refresh this thread, but I am still observing sold auctions appearing in the data from the API.
The following auction (Aqir Hivespawn pet) appeared in the Blackhand server data dump from apx 7:33 CST:
{“auc”:1746318208,“item”:82800,“ownerRealm”:“Blackhand”,“bid”:0,“buyout”:100,“quantity”:1,“timeLeft”:“VERY_LONG”,“rand”:0,“seed”:0,“context”:0,“modifiers”:[{“type”:3,“value”:2834},{“type”:4,“value”:50331655},{“type”:5,“value”:1},{“type”:6,“value”:95174}],“petSpeciesId”:2834,“petBreedId”:7,“petLevel”:1,“petQualityId”:3},
As soon as I noticed I logged in on Blackhand and bought it, likely around 7:34-7:35 CST. Confirmed also that this was the only Aqir Hivespawn pet listed on Blackhand at this point in time.
The next Blackhand data dump at apx 8:34 CST still included the same auction.
{“auc”:1746318208,“item”:82800,“ownerRealm”:“Blackhand”,“bid”:0,“buyout”:100,“quantity”:1,“timeLeft”:“VERY_LONG”,“rand”:0,“seed”:0,“context”:0,“modifiers”:[{“type”:3,“value”:2834},{“type”:4,“value”:50331655},{“type”:5,“value”:1},{“type”:6,“value”:95174}],“petSpeciesId”:2834,“petBreedId”:7,“petLevel”:1,“petQualityId”:3},
(Yes, I realize copy/paste is redundant/pointless here, but doing it anyway since I know in my head the strings came from different files :p)
In particular the “auc” field is the same, which I presume represents a unique ID for each auction, which would indicate that these lines are, in fact, the same auction.
The next Blackhand data dump at apx 9:35 CST did not include this auction.
Unless the API data isn’t meant to be real time (it did seem to be real time pre-8.3, though obviously I am not privy to Blizzard’s intended behavior on this), it seems there are still some situations where sold auctions are appearing in a subsequent data dump at least for some amount of time after they no longer exist.
Thanks for your time!
non-existent lots are still displayed on Russian realms, not as long as before, but still, sold lots should not be displayed in the dump after an hour or two as now
Does anyone know how to identify sold auctions vs. cancelled for instance?