The article is over reporting the quality of the data. There's no data with them in the strait, just on either side. The logical conclusion, if it is actually a single ship, is that it crossed the strait. I think it's far more likely that the Indian shipyard that dismantled them has a habit of selling the transponder data for profit, and the Japanese owners want to squeeze their dead ships for 110% revenue, so look the other way. I suppose the only purpose of these transponders would be misdirection during a war, but they seem to have just gotten their money's worth.