When applying crossfades to audio tracks, the audio is still popping, as though no crossfade has been applied. This occurs in new sequences, upon export and after deleting audio render files. It's also happening regardless which type of crossfade is used. The only workaround I've found is to send the audio to Audition and export out a mix and reimport into Premiere. It's not a necessary step for basic projects and crossfades should just work.