Wired Access to WAX610Y and WAX620 APs over Tagged Management VLAN

I have a medium-sized switched network with approximately ten (10) MS108EUP(s) that are all interconnected via LAGs using tagged VLAN trunk ports. The MS108EUPs serve as the backbone switches for my wireless network and surveillance (camera) system in a 56-unit condominium complex.

I also have a mix of ten (1) WAX610Y and WAX620 APs all running firmware version V10.8.12.9.

The network has multiple VLANs enabled:

vlan1-default

vlan100-trusted

vlan110-wireless

vlan120-cameras

All of my network switches have been configured with a VLAN Management ID of 100 (trusted).

I also have a MikroTik hEX S router running the latest RouterOS 7.18 along with Dude for monitoring my network infrastructure devices. I am not using Insight Manager. The MikroTik is being used for inter-VLAN routing.

The switched network is working perfectly for all my access devices as well as remote management of the MS108EUP switches over VLAN 100. Additionally, using Dude with both ping and http probes for monitoring the health of my infrastructure devices has been working perfectly up until recently.

I am in the process of moving my wireless APs from untagged access ports with PVID 1 to tagged access ports with PVID 100 in preparation for isolating all my wireless traffic to a dedicated VLAN 110.

I have created 2 SSIDs on each of my APs:

1) Public wireless access (VLAN 110)
2) Trusted wireless access (VLAN 100).

Of course, I wanted to continue to remotely monitor and manage the APs, so I configured the LAN port on my APs to disable untagged traffic and setup the Management VLAN ID to 100.

Since doing so, I am experiencing numerous timeout errors trying to access the APs via ping (ICMP). Additionally, I am unable to reliably access several of my WAX610Y APs via the web management interface from VLAN 100 on my wired network.

Interestingly, I have had no issues connecting wirelessly to the SSID that is associated with my trusted VLAN 100 network. The web interface is responsive, and everything works as you would expect.

Why am I unable to reliably connect to my APs over the wired management VLAN?