I had the guest network disabled on my Asus router.
I just turned off my Asus and Tp_link wireless routers and swapped in an Asus ZenWifi AX pair of mesh routers. I'm no longer having the issue. The rest of the topology is the same. The router node has an ethernet cable to my TP-Link wired router (which is connected to my cable modem). The other mesh node is connected with an ethernet backhaul to the mesh router. All devices in the house are now connected to the single SSID exposed by the two mesh nodes. Requests to the printer are now instantaneously handled and connections to other machines on the network work immediately.
So it must have been something with the ASUS RT=AC3100 wireless router.....
I just turned off my Asus and Tp_link wireless routers and swapped in an Asus ZenWifi AX pair of mesh routers. I'm no longer having the issue. The rest of the topology is the same. The router node has an ethernet cable to my TP-Link wired router (which is connected to my cable modem). The other mesh node is connected with an ethernet backhaul to the mesh router. All devices in the house are now connected to the single SSID exposed by the two mesh nodes. Requests to the printer are now instantaneously handled and connections to other machines on the network work immediately.
So it must have been something with the ASUS RT=AC3100 wireless router.....