
I edited an option set to include an extra option, "Camping". I then downloaded an advanced find including that option set field, because I wanted to update a few hundred records at once. When I went to import the changes, I get an error message saying a different option in the set, "Play and Recreation" cannot be mapped. I have no idea how or why, because it wasn't the field I changed, and I'm importing straight from an advanced find, so the option is definitely there. What could be the cause of the issue?
Probably due to some broken customization or historical data issue. We cannot comment without seeing data and customizations.
Check the file for that particular data and see the record from which it is getting referred. Then you can go from there.