Google now not only acknowledges the bumps that some users noticed but also tries to reassure them that those bumps are nothing to worry about:
Pixel 8 phones have a new display. When the screen is turned off, not in use and in specific lighting conditions, some users may see impressions from components in the device that look like small bumps. There is no functional impact to Pixel 8 performance or durability.
For instance, here’s one photo from Google’s official Pixel forums:
I bought one during the Black Friday sale and haven’t seen any bumps so far. Had the phone about a week.