Incorrect path to album images

Hi,
I’m currently testing simply gallery, it mostly seems to work very well. However, I’m having an issue that no images show when you open an album due to incorrect image src.

1. My images are stored at a separate location (https://images.mydomain.com/wp-content/etc/) using the WP Offload Media plugin to save images to Amazon S3.

2. Gallery created and inserted as a block on my page – works perfectly. All images load correctly with src=https://images.mydomain.com/wp-content/etc/

3. I create my album and assign the gallery to that album. Insert album on page – no images load. Inspector shows that image src=https://www.mydomain.com/wp-content/etc/ thus cannot be found.

Any ideas?
Many Thanks