Incorrect Client Name Near Logout Button

[enum8]

Hello, 

I have a problem with my Prestashop. 

How it looks like?

1. Clearing cache in admin panel - by me.

2. Some user logging in (for example "Test User")

3. What happen if another user login to shop:

- First and Lastname are bad displayed, always (for every client) - "Test User" (near Logout button)

4. In "User Profile", client information are correct, only issue is displaying first and last name near "Logout" button. 

I'm sorry for bad english, just wanted to explain as best as I can, what my problem is. Attaching screenshot.

Edited January 29, 2016 by enum8 (see edit history)