Update.
Many attempts of having the Chromecasts come alive in a stable manner (they would only work immediately after rebooting the router). I tried the suggestions offered by people here, including disabling the STP (I could not get past CTF enabled for level 2 acceleration, however), IGMP...
I just configured two of the Chromecasts for the "preview" program in an attempt to have a newer firmware than the stable one. The pain now is to actually have these chromecasts connect and sustain a connection to the network until they upgrade themselves. It is a game of...
One update.
Following a thread in Google forums on the Chromecast issue with overloading Wi-Fi routers upon waking up (https://www.engadget.com/2018/01/16/google-chromecast-messing-wifi-connections/), I note that the behavior I am experiencing with the Chromecasts v1 are somewhat similar...
One mitigator is to configure the RT-AC3200 to reboot on schedule, say every week or so. Administration - System - Basic Config. I have set mine on regular reboot because it has let me down on occasions, one particular one during a trip, locking me out of my whole house automation/surveillance...
Chromecast is the only one device that has issues. I do have 3 Chromecasts v1, all of them have the issue, and all of them started having the issue around the same time (is Google killing them? :)). Because of this behavior, I did suspect either (1) Merlin version was breaking the chromecasts...
Reporting this there to see whether others have similar problems and/or solutions to suggest.
Issue:
Chromecast v1 devices (the ones which only support 2.4 GHz band) are constantly being ejected from the wireless network. Reconnecting them requires a reboot to the Wi-Fi router so that they can...