According to various user reports that have been subsequently confirmed by Android Police, placing a Pixel 3 or Pixel 3 XL on the Pixel Stand could potentially cause ambient notifications to “break”. It has also been reported that photo frame mode is also busted for some users. For those unfamiliar, photo frame mode is pretty much as its name suggests, where your phone when placed on the stand can act as a pseudo photo frame.
As Android Police notes, these are issues that not many people might have noticed because not many people may be using ambient notifications to begin with, or how many users out there actually bought the Pixel Stand. However bugs are bugs and should still be fixed, and the only temporary workaround is to reboot your phone, although there is a high chance that these bugs will return even after that.
Google has since confirmed that they are looking into the issue but when exactly we might be able to expect a fix is unclear.