They voted for it after saying they wouldn’t:
Detroit's poll books were found to be 72% out of balance in the August primary. Also, in 2016, vote totals for 59% of the Detroit precincts could not be reconciled
(mostly because of finding too many had voted according to explanation from source)
This info on former book audits is readily available to anyone who wants it.
This year Detroit books are speculated to be in worse shape but this has not and cannot be confirmed at this time