Best answer by Dinh
I got today lg g7+ thinQ and the I can only see phone number with no name.
The pixel xl has android 9.0 while the lg g7+ thinQ has android 8.
Could that be the reason? Considering the lg g7+ thinQ is a newer version than the pixel xl.
Who was the caller carrier?
if the callers were Fido/Rogers or some land lines, their names might show up. Also, If you save your contact numbers in your phone (normally you can synchronize with google contact with android phone), their names should show up with the number.