Clicky audio after exporting a 'Goanimate video'

I’ve been using the website to make some animations for work.

I used audacity to chop up all the dialogue into lines and it all sounds fine when listening to it in the editor, but after export to mp4 there are lots of clicks being generated. I have opened the mp4 files in audacity and am trying to find the clicks so I can smooth them out with the pen tool but I’m having a lot of trouble finding them and they are quite quiet (but still very audible).

I have tried using the scrub tool, but when i do the playback is so full of clicks that I can’t hone in on the one that is audible when playing at normal speed. I’ve tried using the spectrogram view but, the clicks, I guess are nestled in at the same frequencies as the dialogue so I’m wasting lots of time notch filtering out random frequencies.

Do you have to use MP4 format? Does the problem happen with WAV files?