"I hear a constant clicking + high-pitched squealing noise is noticeable whenever the phone is unlocked," wrote one Pixel 2 owner.
"Turning off NFC stops the clicking but can still hear faint squealing sound. Very noticeable during a call since handset is pressed to your ear. Does not occur when the screen is off or locked. Very frustrating indeed."
Google hasn't responded publicly on the forums, but one user posted a private message from Google Support saying the whirring and clicking sounds are a "known issue" that will be addressed in a patch scheduled for next week.
Several users confirmed that switching off NFC stops the clicking sound and makes the high-pitched noise "barely noticeable".
A number of users report having returned their new Pixel 2 for a replacement.
There are also a few postings about Pixel 2 XLs making the same noises, but the sounds are reportedly louder on the Pixel 2.
Additionally, more problems are surfacing with the Pixel 2 XL's OLED screen. Besides the burn-in issue and complaints of low-light graininess, 9to5Googlereports that its Pixel 2 XL review unit's display is showing a "black smear".
This issue is known to occur on OLED displays as they age but, as the site notes, the Pixel 2 XL's smear is worse than that found on a four-year-old Galaxy S4.
A Google spokesperson told the publication that it is investigating the smear problem.
"The demand for Pixel 2 and Pixel 2 XL has exceeded our expectations, and we're thrilled with the positive reaction to our new phones, both from the reviewers who have tried and tested our devices thoroughly and from consumers who are switching to Pixel," Google said.
"We take all reports of issues very seriously, and our engineers investigate quickly. We will provide updates as soon as we have conclusive data."