Oh, see the problem, in the official Games the victory is played until you skip the message so Essentials did the same (I also do the same but with an Ogg and with loop points).
If you don't want that : in "PokeBattle_Scene" replace
pbBGMPlay(pbGetWildVictoryME())
by
pbMEPlay(pbGetWildVictoryME())
and
pbBGMPlay(pbGetTrainerVictoryME(@battle.opponent))
by
pbMEPlay(pbGetTrainerVictoryME(@battle.opponent))
I didn't see any other bug with the repeat of the music. I recommand you to convert some important music to ogg and put the LOOPSTART and LOOPLENGTH tag if you don't want any problem with that ^^