LocalStorage UUID disappearance

I’m working on a project that needs to keep a UUID between page changes, and with Firefox, this id is always lost.

The UUID is stored directly as a string and is present before changing page. When another page is loaded, the local storage entry is missing.

I tried to disable the tracking protection, adblocking and such, but nothing to do, the UUID still disappears.

What’s happening ? Is it normal behaviour ? Is there a configuration option to keep the UUID in the localStorage ?

Thanks a lot.