Dead Server Redirect

Technically speaking, not being able to RDP to the server doesn't necessarily mean it's powered down. If by chance that server is still powered on but services are offline, the network stack could still be alive and communicating. In any case, assuming the F5 VIP is on the same network as this server, and you can perhaps reach other VIPs on the F5, then it seems purely like a networking issue. The most common thing that happens when you reuse an IP address address is that ARP doesn't reset immediately. A router or switch on that network may still have the hardware address of the old device. Your best bet may be to coordinate with whoever manages the network devices on that network to 1) remove the ARP cache, and 2) sniff the traffic destined for this IP address (to see where it's going).