There have been multiple proposed release dates for the Pixel 4a, Google's mid-range successor to the popular Pixel 3a. While May 12 was likely the original release date for the Pixel 4a, Jon Prosser is now "100%" on a new date.
https://www.notebookcheck.net/Leaker-is-100-confident-of-imminent-Google-Pixel-4a-release-date.483169.0.html