==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release):                         iRedMail    0.9.9  / iRedAdmin-Pro    3.1 (MySQL)
- Deployed with iRedMail Easy or the downloadable installer?
- Linux/BSD distribution name and version:                                 Ubuntu 16.04
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):     MySQL
- Web server (Apache or Nginx):                                                  Nginx
- Manage mail accounts with iRedAdmin-Pro?                               Yes
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

Hello there.

Attachments from  google mail service (gmail) to my server are shown in pairs. However, the file attachments from other (hotmail, yandex ..) mail services do not have this problem. I showed it in the pictures below.

Have you ever seen anything like that before?