RDP across Transparent Bridge

[mitchadmin]

My equipment is as follows:

1*Cisco Smart Switch
1*MicroATX, dual NIC, Atom based PC - OPNSense 18.7, transparent bridge configuration
1*Laptop
1*Desktop PC
1*Hyper-V server (on the 192.168.19.0 subnet)

Office switch > OPNsense > Cisco switch > PC, laptop, server

The switch is attached to the office switch, exposing it to four networks:
192.168.0.0
192.168.19.0
192.168.20.0
10.0.0.0

Scenario:
IDS/IPS is off
Can RDP to devices external to the office through the bridge
Can RDP to devices on 192.168.0.0 subnet
Can RDP to devices on 192.168.20.0 subnet
Cannot RDP to the 192.168.19.0 subnet

When IDS/IPS is enabled, I can only RDP out to URLs and not their actual IP addresses

Very few trace routes succeed, the successful ones are to devices on the 192.168.20.0 subnet

What can I do to configure this setup properly?