[Windows] 2.7-rc on server with DCO breaks client-to-client

Hi,
I have a working subnet configuration for all my Windows 11 computers. I've upgraded all my client from 2.6.x to 2.7rc3 with success (they were already usin dco driver).

My server currently run 2.6.17 with witun drivers and all works fine:

• ✅ client <> server
• ✅ client <> client

When I upgrade server to 2.7rc3 (changing adapter from wintun to dco and with windows-driver wintun removed) without any other configuration changes, I have:

• ✅ client <> server working
• 🔴 client <> client ⏩ unable to communicate between them (ping, tracert, smb)

Same issue with 2.7rc2 and 2.7rc1.
I didn't see any error or output change in client and server logs explaining this point.

Here are my configurations:

Server

port 5000  
proto udp4  
  
dev tun  
dev-type tun  
  # commented for 2.7  
windows-driver wintun  
  
mode server  
tls-server  
  
ping-timer-rem  
keepalive 10 120  
  
dh none  
auth none  
cipher AES-128-GCM  
data-ciphers AES-128-GCM  
allow-compression no  
  
topology subnet  
push "topology subnet"  
ifconfig 192.168.2.1 255.255.255.0  
server 192.168.2.0 255.255.255.0  
  
  # for each client, I have: 'ifconfig-push 192.168.2.xxx 255.255.255.0'  
client-config-dir ./ccd  
ccd-exclusive  
client-to-client  
max-clients 25  
  
sndbuf 524288  
rcvbuf 524288  
tun-mtu 1500  
push "tun-mtu 1500"  
  
explicit-exit-notify 1  

Client

client  
dev tun  
proto udp  
remote mydomain.com 5000  
  
resolv-retry infinite  
reneg-sec 0  
  
nobind  
pull  
  
persist-tun  
remote-random  
tls-client  
mute-replay-warnings  
  
remote-cert-tls server  
cipher AES-128-GCM  
auth none  
  
verb 3  
mute 10  
script-security 2  
auth-nocache  
  
sndbuf 524288  
rcvbuf 524288  
  
explicit-exit-notify 1  
  
pull-filter ignore redirect-gateway  
route-nopull  
route 192.168.2.0 255.255.255.0 vpn_gateway 300  

Does I missed something or is that an issue?
Thx!