How does a re-render affect useRef values

Question

At the top of my component I define a variable with useRef like below.

const data = {
    item1 : useRef (null),
}
console.log (data['item1'].current?.srcObject)

Now as the logic proceeds through the component the value for item1 is set up. The ref is attached to a video element. And at certain points the component re-renders. The console.log prints the value of the srcObject upon the first re-render and the second. But on the third that value is lost. The srcObject is not explicitly changed in between the re-renders.

I don't fully understand refs but I'd like to know how these values are retained or destroyed. Of course I get that they maybe case specific but I'd still like to get the general idea.