My custom sound font won't play properly

I created a sound sample in polyphone that I wanted to use in a drumline score I'm working on. (I Tested it in Polyphone's virtual keyboard and it works fine). However, when I go to place the note that it is assigned to in musescore, it only plays a second of sound and not the full 5.3 second audio that it should be (even if a tie/whole note is placed). *Also I only wanted the sample to play on one note, not multiple
Is there a way to fix this?