I really don't know how that could have happened. It could be an error in one or the other. The best thing to do is to probably just call the court and inquire of them as to what to do. Most times the clerks will be very helpful in clarifying this type of situation for you.
That typically would only happen if you or someone on your behalf requested a postponement of your jury service.
You should call the 1(800) 778-5879 (SRV-JURY) number on the summons and ask to speak with a jury service representative.
Frank W. Chen is licensed to practice law in the State of California. The information presented here is general in nature and is not intended, nor should be construed, as legal advice. This posting does not create any attorney-client relationship with the author. For specific advice about your particular situation, consult your own attorney.