Hi webmasterF1 ,
Thanks for reaching out to us! I hope that you had a great weekend. 😃
From what it sounds like, WP-Rocket is removing the Font Awesome script that Buttonizer imports.
Is your site perhaps using WP-Rocket's Remove Unused CSS (Beta)?
From our experience with past issues, this seems to be removing Font Awesome causing the icons to disappear.
If so, could you try and add this into the CSS safelist directly under Remove Unused CSS (Beta)?
Please let me know if this solves the issue for you. 😄