Item failed inspection and sale cancelled with 'item cannot be exported'

[ajmayo2005]

I purchased a vintage HP65 calculator from a US seller to be shipped to my address in the UK. I have purchased several vintage calculators through eBay from the US without any issues previously.
The item was shipped via eBay's global fulfilment service. When it reached the inspection phase, it was abruptly marked 'failed inspection' and then the sale was automatically cancelled by eBay with the status 'This item cannot be exported'.
Both the seller and the buyer (myself) were immediately refunded. I contacted eBay because I was concerned that the item would be destroyed and not returned to the seller. The eBay agent contacted logistics and has assured me that 'as a one-time exception' the item would be returned to the seller, although the seller has not received any notification to that effect.
This means that a valuable and irreplaceable item might still be arbitrarily destroyed. 
The eBay agent was unable to determine why the item failed inspection. It did not contain any batteries though it was shipped with the original charger (however I have successfully purchased items previously from the US which did have both batteries and charger - the batteries are old and fully discharged and are not lithium cells in any case). 
But as I said, there were no batteries included. Nor is there a question of the item being a fake - nobody is faking these things. 
Why has this happened and how can a seller or purchaser ensure the issue does not occur in the future.

[plpmr]

"The eBay agent contacted logistics and has assured me that 'as a one-time exception' the item would be returned to the seller,"

that clearly is duff information, as the seller kept the sale money they would not get the item back.

[tobiasd4]

In the UK, if item is not allowed to be exported, Pitney Bowes dispose of item at auction to recover their losses.

I assume same applies in USA.

Seller never gets item back.

[ajmayo2005]

Hi folks. Oddly, the reply emails that were triggered went into my spam folder.

I did have two eBay representatives follow up on the case. They were pretty useless because it appears this inspection stage is pretty walled off from the rest of eBay and so it's impossible to determine why an item failed inspection or indeed what happens to it (in the case of the US at least, I understand Pitney Bowes are involved in the UK).

It was suggested batteries were the cause - but none were in the shipment and I confirmed this with the seller.

Anyway, I will simply not purchase any more items that ship through eBay's own international fulfilment.