There is no reason to believe that this is an unusual event. The position of Secretary of State in the United States is not a long term position. Look at the last eight. These span almost 25 years.
Name: Edmund Sixtus Muskie
State of Residency: Maine
Non-career appointee
Appointment: May 8, 1980
Entry on Duty: May 8, 1980
Termination of Appointment: Jan 18, 1981
Name: Alexander Meigs Haig, Jr.
State of Residency: Connecticut
Non-career appointee
Appointment: Jan 22, 1981
Entry on Duty: Jan 22, 1981
Termination of Appointment: Jul 5, 1982
Name: George P. Shultz
State of Residency: California
Non-career appointee
Appointment: Jul 16, 1982
Entry on Duty: Jul 16, 1982
Termination of Appointment: Jan 20, 1989
Name: James Addison Baker, III
State of Residency: Texas
Non-career appointee
Appointment: Jan 25, 1989
Entry on Duty: Jan 25, 1989
Termination of Appointment: Aug 23, 1992
Name: Lawrence S. Eagleburger
State of Residency: Florida
Foreign Service officer
Appointment: Dec 8, 1992
Entry on Duty: Dec 8, 1992
Termination of Appointment: Jan 19, 1993
Note: Commissioned during a recess of the Senate. Served as Acting Secretary of State, Aug 23-Dec 8, 1992.
Name: Warren M. Christopher
State of Residency: California
Non-career appointee
Appointment: Jan 20, 1993
Entry on Duty: Jan 20, 1993
Termination of Appointment: January 17, 1997
Name: Madeleine Korbel Albright
State of Residency: District of Columbia
Non-career appointment
Appointment: January 17, 1997
Entry on Duty: January 23, 1997
Termination of Appointment: January 19, 2001
Name: Colin L. Powell
State of Residency: Virginia
Non-career appointment
Appointment: January 20, 2001
Entry on Duty: January 20, 2001
http://www.state.gov/r/pa/ho/po/1682.htm