Back in late July, we reported of issues that Pixel 4 XL owners were having with the back glass panel on their phones separating from the frame. At the time, the issue appeared to primarily be limited to the larger Pixel 4 XL and not the standard Pixel 4.
According to a representative for the uBreakiFix store, a faulty connector within
Source: Hot Hardware – Google Pixel 3 Owners Latest To Report Of Swollen Batteries Destroying Their Phones