Private IP goes over Router to WAN

Hello i have a strange Problem and cant find the answer.

I have a Netgear R7000 Router with FreshTomato Firmware 2019.3.118 -beta K26ARM.
Settings:

Router: 192.168.1.1 (DHCP&DNS Server)
PC1 192.168.1.101 @ 1Gbit NIC
PC2 192.168.1.13 @ 1Gbit NIC
Conneced with a 08/15 Gbit Switch Switch.

This is working fine.

Now the Problem:

PC1 and PC2 are connected with a 10Gbit NIC with a static IP no Switch or Router. Point to Point.

PC1 192.168.2.200 PC2 192.168.2.201 Subnet 24

But...

Private IP goes over Router to WAN