SRX5308 PPTP VPN Multiple simultaneous connection fail due to duplicate IP Address assignment

Background:

SRX5308 Firmware 4.3.1-22 

PPTP VPN

  IP Address Range: 192.168.18.2 - 192.168.18.26

2 VLAN's

  1 - 192.168.16.1/255.255.255.0  DHCP Disabled

  10 - 10.10.0.1/255.255.255.0  DHCP Enabled

Clients: Windows 10 normal configuration of VPN is to use DHCP for connection.

Problem:  The first person connects to the VPN and traffic flows through VPN

PPTP Active Users shows:

    VPN_USER    Remote IP 192.168.18.3   PPTP IP 192.168.18.3

When the second person connects to the VPN, the connection is successful but not traffic flows through the VPN.

PPTP Active Users shows:

    VPN_USER    Remote IP 192.168.18.3   PPTP IP 192.168.18.2

    VPN_USER    Remote IP 192.168.18.3   PPTP IP 192.168.18.2

I suspect but cannot confirm that problem is the duplicate IP Address.  I tried forcing the IP address on the second machine to192.168.18.20, this did not resolve the problem.  I've looked at all the PPTP server settings and can't find anything that controls the IP address assignment.

I'm posting here since the 5308 is end-of-life

Harry