WordPress is stripping escape backslashes from JSON strings in post_meta
Doesn’t look like there’s any way to avoid it. The update_metadata() function, which is ultimately responsible for saving the meta, explicitly runs a stripslashes_deep() on the meta value. This function will even strip slashes from array elements, if the value were an array. Theres a filter that’s run AFTER that called sanitize_meta, which you could … Read more