Oh no! Sorry to hear this folks. Could you all please share links to affected page so I can see? Or screenshot if that’s not possible?
The update upgraded FontAwesome4 to FontAwesome5. The icons are different in v5 so the upgrade included a migration script that is meant to fix those icons which are different so they don’t break. Sounds like there’s a flaw with that. Can fix it if you can show me which are the broken icons?
Thanks.
PS. A manual fix will be to go into wp-admin > Sticky Side Buttons > Settings > and re-select the icon for the affected buttons.