Insecure Image Loaded when Hummingbird Active

I am getting an url security error when hummingbird is active. It says one of the images on my page is being pulled from an insecure url – http: instead of https:
When hummingbird is deactivated is is fine. When activated it is not.
I am using the AVADA theme and it is one of the default images that is showing in the error:
An image with an insecure url of “https://www.durametsolutions.com/wp-content/themes/Avada/assets/images/page_title_bg.png” was loaded on line: 595 of https://durametsolutions.com/.
This URL will need to be updated to use a secure URL for your padlock to return.

I did not have page caching or asset optimization turned on when I got the error. I turned them both on just to see and still got the same result.
I also tried clearing the caches but that made no difference either.

Any ideas you can give me would be appreciated.

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