Users swapping PHP server and session vars randomly

Hi

I'm experiencing a strange situation.

The users are getting other user's $_SESSION and $_SERVER vars randomly.

Example:

If I print $_SERVER['REMOTE_ADDR'] I receive different ips (randomly):

[Removed - Please attach images directly to the thread]

After some time
[Removed - Please attach images directly to the thread]

After some time


The same occurs with $_SESSION var.

Some idea how fix this?

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Server information:
cPanel Version: 76.0 (build 20)
Apache Version: 2.4.38
PHP Version: 5.6.40 (PHP site version 7.2)
MySQL Version: 5.7.25
Architecture: x86_64
Operating System: linux (CentOS)
Perl Version: 5.16.3
Kernel Version: 4.9.120-xxxx-std-ipv6-64