Replaced battery, but now wireless charging isn't working properly

Hi,

This weekend I swapped out the battery in my Pixel 4, which went pretty smoothly. I don't think I damaged anything internal in the process. However, since then I have noticed that wireless charging isn't working properly.

When placed on the charging pad, the phone starts to charge just fine. But then a few minutes or even an hour later, the charging pad is no longer recognised.

If I take the phone off the pad and place it back on, nothing happens. However, if I take it off the pad and squeeeeze it, as if I'm forcing the back of the device to stick better to its adhesive, I can put it back on the pad and it will be recognised again for a few minutes. As the wireless charging coil is attached to the back of the glass I don't see why this should help, but it does.

Does anyone have an idea of why this would happen - did I damage something internal without realising, or fail to put something back properly?

Thanks in advance for any help.