I have a Deco M4 AC1200 whole house - but that selection is not available in the model drop down. I could not find or M4 AC1200 anywhere as an option with other product lines either. 

I

I have several wi-fi networks in my home.

When using any of several Amazon Echo Show devices in the home - when those devices are connected on the tp-link network the following example interactions do not work

"Alexa spell [any word of your choice]"  she then spells the word, but does not display it

"Alexa show forecast" she then says here is the weather in [my city] and shows just a blank screen

Alexa is showing a prompt for a video story - touch the screen to show the story - Alexa reports "here is your story" again only showing a black screen no video/no audio,

If I switch the Echo devices to any other network in the home - all of the above commands work perfectly, showing screen/pic instantaeously.

This TP-link router is dedicated to IOT, and is not visible to my other in-home networks.I have multiple other routers directly attached to my ISP Modem, just like the tp-link is- again, they work fine. All networks are operating on separate channels.

Probably not related, but the speedtest.net  on the TP-link wireless networks is also significanlty slower than other networks attached to the same ISP modem (about 1/3 the speed, with the TP-link running at 70-77Mbps)