@Paul_Higgs

Did you also swap the EnGenius AP with the eap225 to isolate the issue to the AP? If so maybe try a factory rest on the AP.

  @D-C  I did not provision the 201 VLAN in any of the Omada devices.

I guess next step will be to define VLAN 201 in Omada but only allow it in the switch that pfSense connects to then try also with the switch that is on the other side of the TP Link router.

I would rather not 'factory reset' everything as these VLAN IDs have never been provisioned before, but perhaps that is a good way to go - New Year, New Configuration

@Paul_Higgs, you could factory reset the AP and set it up in stand alone mode to test.

  @Paul_Higgs I will give that a try over the weekend however, as previously noted, I believe the problem is more with the TP-Link switches or router than the AP as

a) a third party AP connected to the existing switch does not work and 

b) captures from the Omada management system show the DHCP DISCOVER packet on the wired side of the AP, but no packet is seen on the VLAN at pfSense.

@Paul_Higgs, in post #9 you said "NOK with TP-Link EAP, but OK with Engenuis AP" so I'm getting a little confused reading "a".

Paul_Higgs wrote

  @Paul_Higgs I will give that a try over the weekend however, as previously noted, I believe the problem is more with the TP-Link switches or router than the AP as

a) a third party AP connected to the existing switch does not work and 

b) captures from the Omada management system show the DHCP DISCOVER packet on the wired side of the AP, but no packet is seen on the VLAN at pfSense.