Audio pops / glitches in exported video - doesn't happen in timeline

I'm running macOS High Sierra version 10.13 and Premiere Pro 14.8.0 (build 39).

I've been trying to export a video, of which sounds fine inside of Premiere, but then has audio pops / small glitches once the video has been exported. 

It's a very similar situation to what is described in this community post from 2019: https://community.adobe.com/t5/premiere-pro-discussions/audio-pops-only-in-exported-video-no-audio-pop-in-timeline/m-p/10513179

I checked the video that was posted there as an example, and it's a very similar noise. Similarly, it only seems to happen during transitions in the video, when footage / audio is fading in an out.

I've tried various different ways of exporting, and nothing seems to work. I'm also not keen to update Premiere, because in order to do so I would need to update from High Sierra to whatever the latest macOS is, which will mean some other programs / plugins will cease to work.

Any help would very much be appreciated.