Some Pixel 4 XL owners report the glass backs peeling off of their phones.

We’ve asked Google for comment. However, it doesn’t appear to be treating the peeling backs as a recurring problem. Another Reddit user reported having to negotiate with Google to get their phone fixed under warranty.
It’s not certain how widespread the problem is, but the timing is less than ideal. Google appears close to releasing its budget Pixel 4a phone, and claims of poor build quality (even if for a different model) might hurt the 4a’s chances.