This is likely based on the AliTV board that a lot of devices uses.

I made a list of what works, what doesn't, and how it works here:

https://www.reddit.com/r/ShieldAndroidTV/comments/a1uc06/alternative_remote_for_shield_tv/eatjdip/

I have two of these, they came with my my two bedroom Chinese Android TV OS boxes. They work pretty good. Have not tried it on my shield yet, I’m content with the Shield controller.

Lol - https://images-na.ssl-images-amazon.com/images/I/41Y2zgLzLwL.jpg

Did you also unpair your Shield remote when testing the Fire TV 4K remote voice search?

Got the BT version of this controller for my Shield and it fails to connect

These look like the ones from Banggood. They work great for a couple days then you have to pair them again. I bought a box that was supposed to be official Android TV and it had same remote.