I've actually experieced quite a few cases similar to the one you describe. On many occasions I've either noticed that eBay's tracking doesn't update and that the courier's own website gives more up-to-date information than eBay does, or in some cases - such as when the seller has refused to disclose what courier he or she is using and has then posted the item using Evri - the item doesn't appear to update on eBay's own tracking details, and Evri's own tracking proves to be equally as bad! I've also had cases where the tracking has stated "Out For Delivery" but has still not arrived half a week later - and in a few cases, even longer. In other cases I've had items arriving within eBay's estimated delivery timescale, but the tracking still hasn't updated to reflect the fact that the item has been delivered, even after a whole week has passed since I received the goods and have left positive feedback for the seller relating to the item!
In summary I suspect that this is due to a number of problems, namely:
1) eBay's own tracking systems are not synchronised with those of the courier being used to deliver the item
2) eBay's relentless efforts to "improve" the site have only made matters worse, including the accuracy of the tracking details available on the site, and
3) the site seems to be run to such an extent by a severely flawed "artificial intelligence" system that the AI can't make head nor tail of what is actually happening, and as such is completely incapable of providing real-time updates to the tracking system.
