Case-sensitive address matching triggers "Reply All" incorrectly

[Mer0me]

Steps to reproduce

1. Configure Nextcloud mail App for user@mail.com
2. Send an email to User@mail.com

Expected behavior

User@mail.com should be considered as user@mail.com and reply button should only reply to the sender

Actual behavior

User@mail.com is considered as another user, and "Reply All" button is visible. When you reply, the reply is sent to the sender AND to yourself, because of case sensitive address matching.

Mail app version

5.6.7

Nextcloud version

32.0.2

Mailserver or service

postfix/dovecot

Operating system

debian

PHP engine version

PHP 8.3

Nextcloud memory caching

No response

Web server

Apache (supported)

Database

MariaDB

Additional info

No response

[GretaD]

Hello, i can only reproduce it if i have more than 1 email address in 'to' or cc. When i send an email to my own email address but with upper case, only reply button is shown.

[Mer0me]

Hello, i can only reproduce it if i have more than 1 email address in 'to' or cc. When i send an email to my own email address but with upper case, only reply button is shown.

Are you sure ? I've just tested again and on my nextcloud instance (and also on a second one I manage too) , sending an email to my single email address, but with uppercase on the first letter, triggers the "reply all" button.

[GretaD]

See screenshot:

[Mer0me]

Do you send the mail from and to the same address ?
Can you try to send from another address ?