I’m new to this plugin, but it appears to be using an older version of Bootstrap 3+ than the current version, which is 4+, and there are some significant differences in the CSS classes the most recent version of Bootstrap uses. If your Avada template uses a newer version of Bootstrap it could create conflicts in how things display.
Ideally, the LDD plugin would use the most recent version of Bootstrap and scrap the old CSS classes, but that would necessitate a rewrite of a lot of the LDD templates.
