PowerPack Lite – in buttons, icons not displaying?

There appears to be an issue with icons displaying on the buttons created with Powerpack Lite on my website. See the linked page. The four buttons near the top of the page (under the first paragraph of text) all have icons, but they are no longer displaying. When I revert back to Powerpack Lite for Beaver Builder v. 1.2.7.1, they display normally. But when I update to v. 1.2.8, they disappear.

Wordpress 5.3, PHP version 7.2

This is the “Dual Button” module. I am selecting the icon in the menu.

The page I need help with: [log in to see the link]