Issues with DHCP and ARP entries after booting a VM (virtualised pfSense setup within proxmox)

[FischKopp]

Hi all!
I'm having severe issues since the setup of this architecture from the beginning on.
The issue is:
After rebooting a VM (no matter if Windows or Linux) on my proxmox-setup, the VM will get the correct IPv4 from the pfSense (as well a VM) DHCP Server and list the supposed correct ARP entry as well.

But it takes till the first "timeout" of the ARP entry to be able to connect to the freshly booted vm from any other subnet. The only chance to fasten it up is to manually delete the ARP entry from the web interface. I'm able to connect to the target IP from another VM in the same subnet.

The setup of the proxmox host is as following:
vmbr0 - public IP address IPv4
vmbr1 - LAN interface /24 subnet from 10.x.y.z
vmbr2 - DMZ interface /24 subnet from other 10.y.z.a

all VMs listen to a DHCP server on vmbr1 and get their IP from this currently.

Did anyone have such an similar issue or have any idea how to change this?
The issue is not coming up if the VM has a static IP address defined.