However when I try to convert it to a JSON file using either the LottieFiles or Bodymovin plugin, the flicker animation is playing at a significally slower speed. Please have a look at the comparison here: https://imgur.com/a/MUQU10m
I’ve tried converting the expressions to keyframes, both in the plugins and in After Effects itself, but that didn’t help.
I tried and got the same result. Looks like a bug and I would draw the developers’ attention to this bug.
As for the task itself I would not use “seed” if it doesn’t work now and tried to play with the “Offset” parameter in the animator for example in this way
var textLayer = thisLayer;
var text = textLayer.text.sourceText;
var charCount = text.length;
var newValue = Math.floor(random() * (charCount+1)) * (100/charCount);
-1*newValue;