Hello guys!
I think it could be a bug and, if so, I'll post it as a bug in the specific area.
The tween behaviors doesn't work correctly with flipped items just because flipped items are with "-" (minus) before Width/height values.
So, previously (about a year ago, I don't know when the regression happened), it works fine with tuning the Width target in tween event with a negative value (-350 in my case, for example).
But now when the tween is triggered it constantly reports width 0px even with this trick.
It's really easy to reproduce, so I didn't upload a visual example, but I'll do in bugs hub if necessary.
I saw that the old litetween plugin in C2 had the same problem multiple times, so maybe it's a recurrent and "easy" fix for Scirra Team.
Thanks to everyone!
Federico