When exporting lists to a RIS file, the TY field of the RIS file is always 'book' even if the item being exported is a journal article. The result is completely incorrect/incomplete export fields when attempting to export a journal article to, for example, a citation manager.
Reading a bit into the code, it looks like more options are possible, depending on your settings in the leader. Some things like a journal it can't recognize yet, as it would need to look at other fields in the record as well:
Currently the code seems to only look at LDR pos 6 - that's not sufficient to recognize serials or articles. We'd need to look at some other fields here as well.
Bug 12357 might help a little.
*** This bug has been marked as a duplicate of bug 16245 ***