Audio effect not applying to beginning of clips

Hi there,

I was trying to apply a preset audio effect I made onto a video clip, which I have done dozens of times before, and the first few seconds sound muffled then it goes into the correct sound with the effect applied. This happens during playback, and when it is exported. I have made no changes to the software settings, the video clips are the usual format, and I made no changes on the preset. Any ideas?

Thank you!