Zooming in, their map reports that vaccination rates in 94707 are now over 100% -- it's the gray region north of UC Berkeley. Perhaps folks are commuting in to 94707 to receive doses?
These numbers are most likely people vaccinated whose address on the paperwork was zip code Z divided by census? population estimate of people who live in zip code Z.
There's lots of fun ways those numbers can be messed up including (but not limited to), people using a mailing address different from where they reside, census boundaries not matching mail delivery route boundaries, population movements, how people without mailing addresses are counted, data issues in the census, etc.
In the US, we have a lack of enthusiasm for comprehensive and compulsary tracking of where people reside, and as a result, data like this is always going to be messy.
