I think we may have a winner for multiple DOIs for the same record: the article “Allostaffia, a new genus name for Staffia Heinrich, 1999 (Allotheria, Haramiyida) preoccupied by Staffia Schubert, 1911 (Protista, Foraminifera)” has three DOIs in the Crossref search engine (see Crossref Metadata Search). The DOis are
One of these is “defunct” in that it resolves to Defunct DOI but the other two resolve to the same article. I suspect part of the problem is that the article was published in “Mitteilungen aus dem Museum für Naturkunde in Berlin, Geowissenschaftliche Reihe” which has been succeeded by “Fossil Record”. At some point someone has decided to update the name of the older articles to that of the newer journal (see the metadata for the DOIs). It is also likely that we have different publishers handling these journals at different times.
I know we’ve been here before (many times) but I feel that while two DOIs for the same article is unfortunate, three starts to look careless.