Luke's corpse bug when he dies

It's probably related to rush attacks indeed, every time I died I noticed it was to maul's spin or to luke's rush. My guess is that they die while performing these skills, and the game keeps their attacking collision box active even after they die. Strangely I've never seen yoda, rey or solo doing that after dead, but then solo is usually a one hit thing, and rey&yoda both have these abilities a bit different from the ones luke and maul have, as even if you block rey's and yoda's you take damage, whereas blocking maul's or luke's effectively blocks the incoming damage