SSLVPN with .3 IP addresss 0 bytes

Hello,

on our FortiGate 6.0.6, a few FortiClient VPN 6.0.5 users reported, that when they are assigned an IP address with x.y.z.3 at the end nothing works. If a user gets x.y.z.1, x.y.z.2, x.y.z.4, x.y.z.5, etc. all the corporate resources are fine.

We've noticed that with two different values of z, and with two different users, so it's not a user problem.

I go to Fortigate Monitor -> Firewall User Monitor, and I see Traffic Volume equaling 0 for such a user.

The SSL VPN Portal Source IP Pool has an address range x.y.z.0/24. 

We think of upgrading the Forticlient to the latest 6.0.x version (what's the latest?), but it's not available for download. What would you suggest?