Perhaps she was declared dead in 1968 (or "as of" 1968) and her family, then living in Michigan, reported the missing case. Sometimes older cases don't have exact dates or a ton of information because they were reported on many years later based on memory.
John Kaminski
DOB 12-April-1914 Watermill, Southampton, Suffolk, New York
Died 9-July-1988 Togas, Chelsea Kennebec Maine
Buried: Calverton National Cemetery, Calverton, Suffolk County, New York
Spouse Frances Kaminski. She is buried in same cemetery
Source: U.S. Veteran's Memorial: Military Service: 21-Nov-1944 Began (Three months after Edna vanished). 13-Jan-1946 Ended
1950 Federal Census John Kaminski 35 divorced lodger street Andrew S house #5440 Inspector Steele Company. 1950 census is free on Ancestry.com and FamilySearch and National Archives.
Frances nee Oswald Kaminski
DOB 31-Jan-1916
Died 30-May-1985 Maine
She has a first marriage: Francis Mullane DOB abt 1910 Died?
Michigan: In 1952 there is a John Kaminski and Frances. I could not verify if same people
Anyone has access to newspapers.com? In 1953 John D. Kaminski was mentioned in an article. Date of publication 16-July-1953 Waterville, Maine. Waterville Morning Sentinel. His sister married in 1954 in Maine as a second marriage.
Kaminski is a popular Polish Surname
Other Surnames: Oswald, Mullane
Edna's family:
Surnames: Sarter (father), DeWald or De Wald (mother)
Does this solve the case? Probably not, but as a genealogist any lead is a helpful one.
Sister: Elizabeth Kaminski DOB 1912 Died 9-Nov-2001
1st marriage Raymond Campion 8-July-1935 Brooklyn, New York City, New York
2nd marriage Maine 1954 Cocco or Coco (SSI information) She received her card in 1943 New York Elizabeth is John's sister and Edna's sister-in-law. Sorry if this is long. All information is on public domain and all deceased.