I have multiple web views of the same domain that share the same local storage, as expected.
One of them though, is loading a .webarchive file for use when offline.
The web archive is of the same domain, and is loaded using the same base URL.

For some reason, in most cases, the local storage is not shared with this web view when loading the web archive, although if I make that same web view load the actual web page it does share local storage.

I say in most cases, because for some users it works as expected, but for a significant portion of users it isn't sharing.
I think that the main difference between working and not is iOS version. iOS 17 seems to be able to share the local storage but iOS 18 does not. I can't find anything related in the release notes of iOS 18 versions.

There is nothing in the documentation for load(_:mimeType:characterEncodingName:baseURL:), or the header file, that explains anything specific about local storage and webarchive loading.

Does anyone know for sure how local storage is handled when a webarchive is loaded into a web view, and did something change with iOS 18 in regards to this?