I bought a 3-pack of entry sensors (v2) and one of them isn’t functioning properly. I have an equipment cabinet in my home office where I installed some Alexa-controlled LED strip lighting and a Wyze sensor to be used as the trigger. This is also the same room as the sensor hub. The sensor pairs up fine, and it functions flawlessly for anywhere between 10 - 20 mins. Ultimately it winds up just remaining on its current status, or it switches over on its own and then remains there. The red light on the sensor will blink if the state changes, it just doesn’t appear to be talking to the hub anymore. If I delete the device and add it again, it will work for a bit then stops working just as before. Other entry sensors from that pack work fine at 20x the distance. Is this just faulty hardware? All firmware’s are up to date.
What type of equipment cabinet is it? Metal perhaps? Photos of the install? If the red light is flashing then the sensor state is changing locally, but the signal may be blocked by the material of the enclosure. It’s like someone trying to put a entry sensor inside a safe door to catch someone else entering the safe. Good idea, but the metal is blocking the signal out from the sensor body. If you take the sensor out from inside the enclosure, does it work? Open the door so there is line of sight and use some random magnet to cycle the sensor body to see if the hub receives the signal now.
One of the issues I ran into was that the sensor was communicating with the hub, but Alexa wasn’t picking up the state change. I would get a tone on the hub (only available for modification if you have the HMS subscription), but Alexa remained oblivious.
If you don’t have the HMS, you can check this by turning on Notifications for the sensor. If it sends you a notification when it is opened, but Alexa doesn’t respond, something is not right with Alexa. If it sends you the wrong notification, see the next paragraph. 
I had two other issues with sensors not acting right and both were because of User Error when installing. On the first, I mistakenly installed the sensor while it was in the open position. This caused the Hub to be quite confused when opening and closing it. The second mistake I made was installing the small magnet puck upside down to the sensor. This caused the polarity of the magnet to be opposite what it should be and the Hub didn’t like it. The Open\Close was reversed.
In both of these cases, Alexa wasn’t getting the proper Open or Close state change so she wouldn’t run the right routine. That’s when I put my glasses on and realized there is an indentation line on the sensor and magnet that needs to line up.
Yeah it’s metal but I do have the sensor & companion piece sticking out (inside the doors) so they’re unobstructed. Perhaps that doesn’t matter? Now it’s pretty consistently “working” ie reporting a state change, however, when it closes, it almost immediately shows it’s open again.
Is it possible that the magnet is too far away from the sensor when the door is fully closed or that they aren’t aligning level with each other (depth)?
Have you tested the sensor and magnet in other positions like the top of the right door and the back of the top bar? Or perhaps the back of the door and the bottom of the shelf?