I made a fielded (and the fielding is correct) lower third logo at the same resolution (720 x 480) as my video in LW that animates from off-screen lower left to the lower right corner in 30 frames.

When I import the png sequence (or render it out to an RTV first) to SE and enable the overlay, it plays fine. If I set the alpha in the control tree to '150' so that it is semi-transparent, it flickers until the animation ends. I tried the same thing in After Effects and it works correctly.

Can anyone confirm this?