"Reply all" does not work when email is sent with CC

[Marianer]

Hi

My "Reply All" button does not work like it suppoesed to.

In my case an email is sent from user to two email addresses.
One of them is connected to OTRS (TO: field) and another is not (CC: field).
A ticket is created correctly and it gets into one queue, but when i try to reply all, only mail sender adress is putted into "TO:" filed, "CC" field remains empty.

Everything works corretly when email sender puts both adresses into "TO:" field.

Why CC email adress is not filed up when I try to reply all?

Regards
M