It first happened to me in DDQ, on Sunday. I thought it was odd, but whatevered it.
Just now an alliance mate mentioned that they’d been seeing them, too.
Anyone else seen them or heard anything about them?
(Obligatory Conspiracy Theory : It has been claimed several times that times drops are “lol completely random you guys”, but why on Earth are these newly discovered tiles all numbered?)
I’ve saw these a couple times too. Far as I can tell they don’t do anything. The number never counts down or anything. Although I heard if you put them in the Horadric Cube with Wirt’s Leg it opens the Cow Level! 
I saw one last night and press on it. It was a Black tile with a “1” on it and I was playing Blade (he was my highest for black). When I pressed on it it said something about Blade destroys this tile, which I think is what it says on any of the tiles with his icon on it.
So, I have no idea what they are for.
I haven’t seen it yet but maybe it’s their solution to telling us what the strongest color is..?
I would freaking LOVE anything remotely like that!
DBC
was blade your highest guy, or in the middle, if so, that might be a strongest color indication and that would be really nice if it were added somehow.
Here is one team-mate saw the other day, saying “It happened when the board shuffled with no available matches”
I still haven’t seen this yet and I played earlier.. maybe Black is your strongest color? What does the tile say when you click on it?
I think he said there was no indication what it was, he matched it later and it did nothing.
I ran into this as well, it was a 1 on a tile after a shuffle. I grabbed a screen shot of it, maybe Ill dig it up later. It had the standard pop up, and did nothing special when matched away.
The issue has already been reported in the bug forum. The bug appears to be caused by board shuffling while countdown tiles are present.
Dammit you beat me to it. I was gonne say it was due to board shuffling =(
Damn.. I thought maybe they would finally address “strongest color.” Maybe next year 
Ahhh…Diablo II. Maybe D3 will add a hardcore difficulty to MPQ…
man all that retreating will be tough, also loosing a level 166 3* to a lvl 90 team will be game throwing level of rage.