It appears that this issue is specific to our regular avatars. For best results, we recommend selecting the ULTRA REALISTIC avatars.
We also recommend checking your script to ensure you have the correct punctuation and spacing.
Writing it in a paragraph form would help in resolving this.
Once you made changes on the script, you need to click RENDER AUDIO to have updated before rendering the final video.
If in case that the final render does not look good to you. Let us know so that we can fix and refund your used credits on rendering it.