DIFTOW said:

The vocals in the LD 5.1 mix are not isolated completely to the center channel, they still have very substantial volume in the left and right channels, not just a mere echo. Is that how they did surround mixing back then, cause any movie I watch in surround sound today, there is either no vocals in the left and right, or at 'certain' moments in a movie, there are if they are extremely loud, or there is a huge echo.

Only EP4 suffers with some bleed through but i wouldn't say its substantial. If you're getting the vocals loud in the left & right channels then i would check your setup. None of the other episodes laserdisc 5.1 audio has any dialogue in any channels apart from the centre, unless in places where its meant to be.