Guest Network with TP-Link OneMesh

I have just set up a TP-Link Decco AX6600 2-device OneMesh network.  Everything works great wirelessly.  I have some wired infrastructure in my house and decided to use it to leverage their 'backhaul' capability.  I have am wired from the Deco router thru a GS108Tv2 to a GS305v3 to a TP-Link switch.  The TP-link switch is connected to the 2nd Decco unit.  The moment I connect, I lose the ability to connect to the OneMesh guest network.  By elimination and lots of long CAT5 wires, I have determined that the GS108Tv2 is the culprit.  If I go from the router to the GS305v3 to the TP-Link switch to the 2nd Deco the guest network works fine.  I am planning on an upgrade to use the GS108Tv2 in another location but I will not be able to do that if I cannot determine what is disabling the guest network.  I updated to the latest GS108Tv2 firmware today and that did not help.  I have gone thru the switch settings, but beyond static/dynamic IP's and a few other simple processes like firmware updates, I am not familiar with smart switches.  Any suggestions for me to research/learn would be useful and appreciated.