Ambassador Tina Kaidanow, a longtime State Department official who began working in her Pentagon role in September 2018, resigned on Dec. 16, the Pentagon confirmed. Defense News first reported her departure.

…“The department will not provide anything further on this personnel matter,” the spokesman added.

…Kaidanow’s resignation follows four other announced departures within a week.

…Top Asia policy official Randall Schriver would leave after two years on the job, 
…[The] top official in charge of personnel and readiness Jimmy Stewart had resigned after taking the role in October 2018
…Defense Advanced Research Projects Agency leader Steven Walker
…Principal Deputy Undersecretary of Defense for Intelligence Kari Bingen

…[Kaidanow] worked with top weapons buyer Under Secretary of Defense for Acquisition and Sustainment Ellen Lord and the Defense Security Cooperation Agency to boost weapon sales with partner and ally countries. 

Fifth Pentagon official announces resignation in seven days | TheHill

hmmm