Gotta problem, its kinda complicated, but involves the following set up: network set up, subfolder install and involves using the Divi Theme (with a child theme i created), involves the following plugin: WPMU Domain Mapping and Amazon S3 plugin, however I explained it better:
I have made some modifications to domain mapping to eliminate the HTTP/HTTPs bug it has for editing pages with the visual builder. Also, used this filter in my child theme: https://deliciousbrains.com/wp-offload-s3/doc/filtering-urls-in-custom-content/
I am left with ONE bug...when domain mapping is active, it is causing the filtering to not work for the customizer css background image paths.I dont know why, it happens when the content is "posted" to save and only in the customizer css, so somewhere it is hooking in and causing an issue.
Do you possibly know where in the code it is rewriting these paths so that I can make the proper modifications?
I think this is a domainmapping/customizer/s3 issue, so somehow Domain Mapping needs to not do its rewrites and get in the way of things