Roundcube wrong time


I run my mail in a box server with about 20 users. One of them shows an incorrect time in roundcube. It’s two hours less than the other accounts. Only this one user is affected.

The time zone settings in Roundcube are identical to those of other users.
Does anyone have an idea?

The problem only occurs when emails are received from a specific email address

I would talk with the owner of that email, their time could be off on their computer. (External not internal)