I've had a streaming stick +(Model 3810X) for some time now and things have been fine. However some odd issues starting popping up a week or so ago. I noticed my remote(Model shows roku rc392 in system but RC-Al7 under batteries) wouldn't respond when I turned the stick/tv on. Re-paired the remote it works until it gets rebooted again. So I started digging in more. I know the anywhere remote is wifi connected. My router is about 5/10 ft away. So I did a channel survey I moved both 2.5 and ghz to pretty open clean channels. On the reboot to change the channels I noticed when the router was down the remote started working again without re-pair. As soon as it comes back up it loses connect again. I've tried both 2.4 and 5ghz networks no difference.
I know on the older models there was an interference setting you could disable and it fixed most issues like this. However it doesn't look like I have the option on mine in the hidden menu.
I also noticed the device last update time was 10/15 so I'm thinking that could have changed something as well.
I am certainly no expert on the Wi-Fi direct that the remote uses to communicate with the stick, but I do have an idea that may or may not be stupid. If turning off the router gets the remote working consistently, see what channel the remote is using. I don't think you can see that from the network settings since it won't be connected, but you can see it from the "Wireless Secret Screen". To get there you first must get to the "Platform Secret Screen". While ignoring anything happening on screen, press Home 5 times followed by FF (>>), Play, Rew (<<), Play, FF.
It may take a couple of tries. It seems Roku has hijacked the Play button to launch the freaking Roku Channel.
Maybe you can set up your router to use that channel (or maybe you already have and it didn't help).