Existing subscribers can't confirm subscription to an additional list

[franc00018]

Version:

• listmonk: v2.4.0
• OS: Debian 11 (Yunohost)

Description of the bug and steps to reproduce:

When a subscriber is confirmed on an existing list, but subscribes to another list later through a web form, they are not send a confirmation email for opt-in when the double opt-in is active.

I use PostMark as a SMTP and was able to confirm with their data that emails are not sent for people already subscribed to another list but are sent to new people, who are able to confirm their opt-in.

Step to reproduce:

• Have two lists with double opt-in activated
• Have two separate forms, one for each list.
• Subscribe to the first list. You will receive an email to opt-in
• Subscribe to the second list with the same e-mail address

Actual behaviour:

• You won't receive an email for the second subscribtion and your will stay unconfirmed.

Expected behaviour:

• You receive a second email to confirm your subscription to the second list

Screenshots:

[candidexmedia]

Related issue: #455