Had a little "fun" theorizing how this could happen by looking at the colors in the stack, it was very easy to reproduce: http://tinyurl.com/y9ag6lst (click the next button to see each placement)
Honestly, since it's a game that was checked by TTC's notorious quality control, I'm not surprised at such a bug. Remember in-flight Tetris?
Since you're playing on the modern official games, I'm just gonna say this: if you think a floating piece is a bug, wait until they start rising.
Well, it's a valid stack configuration, at least. It's impossible to have a piece floating above a row with zero minos in it, but if there is at least something below then it's possible to create this type of suspension easily. Tetris demonstration diagram That said, this kind of thing could also be a bug if you don't know how it happened (as in, dropped the piece straight down and it happened to not reach the bottom for some reason) but it's hard to say what exactly happened without video. There are definitely some interesting problems out there.
I'd say the colors in the stack give it away though It's very obvious there was a horizontal I piece there at one point, like in your exmaple
Yes, maybe. But how do you know, if the vertical I piece was placed before or after the horizontal one was deleted? 1st one is correct, 2nd one is a bug.
