How many troops in a troop?

Headline in today’s Washington Post:

Turkish Troop Dies; Kurd Rebels Trapped

My first thought: An entire troop of Turkish soldiers died? No – only one soldier. Or as the Post calls him, one troop – in defiance of longstanding English usage that a troop is a group.

Apparently this has been a growing (mis)usage for a couple of years now, though this is the first time I’ve noticed it. Give it another decade and you might see singular “troop” working its way into more lenient dictionaries; until then, the Post is just wrong.