UFW NAT No Longer Works

I set up NAT on my computer the other day and it was working fine. It has now stopped working. I use NAT to connect my PS4 to the Internet through my VPN tunnel. I am using UFW. Here are my changes to the configuration files:

/etc/default/ufw

IPV6=yes
DEFAULT_INPUT_POLICY="DROP"
DEFAULT_OUTPUT_POLICY="ACCEPT"
DEFAULT_FORWARD_POLICY="ACCEPT"                                                               

/etc/ufw/sysctl.conf

net/ipv4/ip_forward=1
net/ipv6/conf/default/forwarding=1
net/ipv6/conf/all/forwarding=1

/etc/ufw/before.rules

#NAT tables rules
*nat
:POSTROUTING ACCEPT [0:0]

#Forward traffic through tun0
-A POSTROUTING -s 192.168.3.0/30 -o tun0 -j MASQUERADE

# Commit(not to delete)
COMMIT

I have also tried to disable my VPN and NAT with the Wi-Fi card as output interface. I also used tcpdump and Wireshark and all I seem to see on the Ethernet card is the PS4 asking who the gateway is and the gateway replying with its MAC address. I also noticed a few MDNS packets. I also looked at the tunnel interface and could not seem to notice any connection from the PS4. The PS4 connects to the Internet using its own Wi-Fi adaptor. I also disabled&reenabled ufw, restarted it, rebooted my computer.

What changed in the meantime?

This is what confuses me, nothing has changed. Well something must have altered the setup.

After more troubleshooting everything works fine on my other Ethernet card. No matter what IP settings I use on this card it won't work again for some reason. The card I am having trouble with is an IntelĀ® i218v. The card works fine when running Windows. The other card which works perfectly on Linux is a Killer E2400 MAC+PHY.

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