Trouble Connecting OpenBeken Devices in 192.168.4.x Subnet Without WiFi AP

Hi all,
I'm trying to establish a 1:1 direct link between two Tuya devices without using a WiFi AP or similar. The soft AP of these devices is on the 192.168.4.1 domain, and I attempted to have some Tuya units obtain an IP address via DHCP in the 192.168.4. range. I also tried setting up static IPs (manually assigned IP addresses within the 192.168.4. DHCP range), but they wouldn't register in the .4. subnet. Is there something wrong with my setup (they work with other subnets) or is this by design?

Tried with this unit to get an IP in the 192.168.4 subnet and it fails too.
So is the 192.168.4 subnet not allowed in openbeken?