While PubMed carries out extensive quality control, Crossref explicitly relies on the accuracy of publisher-submitted metadata. Unfortunately, this means that Crossref records are not always as accurate as PubMed records. 

For this reason, Edifix takes a more conservative approach to automatically correcting your references with data from Crossref than with data retrieved from PubMed. Rather than accidentally introduce errors into your references, Edifix is more likely to insert a warning about differences between submitted references and Crossref, so that you can review the differences yourself and make any corrections that are necessary.