Yes indeed, I remember when it was born at Cotswolds, along with a spotted cub in the same litter I am sure, as zoogiraffe correctly says.
I have a feeling that the female at cotswolds at the time produced some off-spring with shorter tails which was said to be a genetic fault.
In actual fact if you look at this photo closely this animals tail does appear to be a tad shorter than normal.
'Truncated' is the term I would use for that tail- it seems blunter at the end than normal.
If I remember correctly, on the Leopard enclosure label at Cotswold there used to be some information about the birth of the(rare) black cub and maybe also a small photo showing the black and normal cubs as babies at CWP.