You could not be bothered reading the last paragraph of the story, it seems ?
But it is quite possible this is just a case of a long incubation period, unusual but not unknown. There was a case in Australia of somebody who returned from abroad, cleared quarantine and then became ill and tested positive weeks later. She lived in a small country town, with no local cases, and no feasible way she became infected locally. Others have tested negative during their quarantine only to be found positive on the last day....which would really suck !
The 14 days is generally accepted as long