It's been reported several times by now and under many names, but in short it's very evident that the sprite layers are messed up. Just adding my stone here, since the bug is very distracting in some istances where the defeated characters' sprite layer is overlapping the alive fighters and hiding their animations.
Other notable instances of this visual bug besides Big Band's corpse covering fighters are Robofortune's catastrophe cannon, Squigly's dragon charge, Eliza's block and Umbrella's projection lens
Other notable instances of this visual bug besides Big Band's corpse covering fighters are Robofortune's catastrophe cannon, Squigly's dragon charge, Eliza's block and Umbrella's projection lens