Audio problem on export

Hey, I have a very frustrating issue and I hope someone can help.

I'm creating a video loop with sound and everything looks and sounds fine in Premiere. But after export adobe adds a tiny amount of silence in the beginning and the end of the audio file, you can se attachment.

The purple file is correct, before export and the yellow is after export. When I loop the silence  creates a click sound when looped.

I'm exporting in h264 and 30fps.

Have tried many differnt codecs and framerates but I cant seem to solve the problem.

Any ideas why this might happen is much appriciated

David