An “island” that supposedly existed in the Coral Sea has been found to be inexistant. Could it be the famed city of R’lyeh that sank beneath the sea again ? I guess the stars are not right after all for the Mayan end of the world 
I’m not an expert on these things but I’m going to go with “no”. Far more likely that, as the article notes, it’s either a cartographical error or a deliberate falsehood, repeated in multiple sources throughout the years.
We’ll probably find some mapmaker eventually who will admit to making it up for copyright protection purposes.
I looked at this on Google Earth, and, unlike most other islands of similar size (or even smaller) it appears as a featureless dark blob, even when you zoom right in on it. I think it is almost certainly a copyright trap. Not far away there are some smaller, equally featureless and suspiciously circular blobs that are doubtless part of the same trap, although unlike “Sandy Island” they are not named. Both they and “Sandy Island” look quite different from the real reefs and sandbars that are in the area.
If you want to see it, it is an elongated dark (on satellite view) blob, slightly to the north and and about three hundred miles to the west of the northern tip of New Caledonia. It looks nothing like the real islands in the area, more like an inkblot.
On a second viewing, the circular blobs that I mentioned before, that are a bit further west still, just off what are some real sandbars, may be some kind of photographic artifact rather than a deliberate fabrication like “Sandy Island”.
Sounds like it has been lost.