According to this Michigan Senate Report it appears that a voter who has (in apparent good faith) cast a ballot prior to election day may have that ballot nullified if they die prior to election day. Quoting from this report:
the secretary of state and clerks were able to discover and remove approximately 3,500 absentee ballots submitted by voters while they were alive but died before Election Day, which is a commendable accomplishment.
Presuming that the Michigan law requires the voter be alive on Election Day to ensure that their ballot be qualified to be counted (so I'm not questioning a Michigan Statute), is this a common practice in the other states and territories?
As an aside comment, if this is a common practice, it's understandable that election results might be delayed until the County Clerks are able to establish who was alive at 12:01AM on Election Day.
EDITED to ADD: According to the verbal contact with Michigan Secretary of State's office there is no specific statute that authorized the removal of these ballots, however, Michigan does not view a ballot being "cast" until the time of "counting and tabulating" (approximately 8PM on election day). Consequently the event that a voter may consider his vote "cast" (having delivered to post office or dropped) is not what determines if the ballot is legitimate or not.