Parallax background keeps bugging out and not rendering image on export

When uploading a new image into bootstrap studios parallax background, it displays within the bootstrap studio however when exported or using the live preview option the image is not rendered and not added to the html.

To work around this issue, I have previously just have to keep making new parallax backgrounds till one is recognised by bootstrap studio... are there any fixes for this or is this a new bug? (haven't previously seen this issue)

Bests, Ethan