Bug related to reference updates -- problems with accent characters, updated years (Endnote 21.2)

I’ve noticed that when I search for updates to my library references, many times the updated versions seem to have certain errors. Sometimes words with accented letters come back missing them – for example, a German journal with the word “für” comes back with “fr”. What’s going on with that?

Likewise, a lot of older refernces will come back updated with completely wrong dates – a journal from 1920 will show up as 2008, for example (my guess is it was the date that the pdf was scanned.) It happens particularly with journals from Wiley and ACS, but others as well. Is this something that needs to be fixed with the filter for Endnote, or with the publisher, or what?