The hissing or static issue with the latest Pixel Buds remains, despite the release of a firmware update that supposedly addressed the problem. In fact, the hissing issue is noticeable even on units released after Google claimed to have fixed it.
https://www.notebookcheck.net/Google-Pixel-Buds-Audio-issues-live-on-despite-the-release-of-a-firmware-update.482910.0.html