No, being in television myself and dealing with old tapes and such, I can assure you this is not bleedthrough. It is intentionally done. Here is my best explanation...
When MPI did the VHS masters back in the 1980s and 1990s, they had to cut the episodes very tight in order for them to fit on the tape. Sometimes, the music at the end of the act would be cut off early and it would go on to the next act quickly.
The mastering company probably used the same sources that MPI did for the VHS releases. But, in their need to make it sound "polished" and "neat", they put this strange effect on the ends of some acts to make it "sound better"... to the effect that you would keep hearing that echo even after the picture has faded back in for the next act!
And the echo effect would not have been there on the original tapes, there were commercials in between on the original 2" tapes, at least a minute, sometimes two minutes, so I don't think that's the answer.