Without knowing the details :
When you remove the 'virtual' part, that is : running pfSense with 3 real networking interfaces, bare bone, your issue will be gone. I can imagine the vitual interfaces / switch can be set up many ways, some of them could be wrong ?
See also Virtualization ! if you have a Windows 10 (Pro) orMS SErver : use the build in Hyper-V : I've one running iwth Hyper-V, and it works fine. There is a detailed step by step setup guide in the doc.
When a client connects to the Wifi, can you see the DHCP server log 'lease' attribution on the right interface ? What was the IP/mask/gateway/DNS received on the client ? That info should correspond to with the pfSense portal NIC.
pfSEnse doesn't handle the the AP <=> Client radio (wifi) connection.
if the AP is an AP and router, the pfSense portal only sees the IP and MAC of the router, not the IP and MAC of the clients. Ones a first client is logged in, all the others will pass without seeing a login screen.