Unsubscribe action via "manage preferences" by user in browser unsubscribes from all private lists

[dwrolvink]

Version:

• listmonk: v2.4.0 (c668523 2023-03-20T13:50:31Z)
• OS: ubuntu

Description of the bug and steps to reproduce:
When I create a number of private and public lists, create a user and subscribe him to all lists, and send him an email via a public list (not sure if the list type is relevant here), the user will receive the email.

If the user then clicks on unsubscribe he is taken to the browser.
If he then immediately clicks unsubscribe again all is well: he is unsubscribed from the one mail list.

If he instead clicks on Manage preferences and doesn't deselect any list, but immediately clicks unsubscribe, he is unsubscribed from all private maillists. This also applies when he deselects any number of mail lists.

I noticed this when clicking unsubscribe on a test mail. Suspecting there might be a bug only there, I send an actual campaign email using a public list, and repeated the step (manage > unsubscribe without deselecting anything). Again the private mail lists are unsubscribed.

No option to unsubscribe from all future mails is ever selected.

This last mail was sent after adding the user to all the private lists.
I tried creating an entirely new campaign, but to the same effect.

I'm guessing there is an update action that lacks the private lists which then mistakenly unsubscribes the user from all private list.