Is it dangerous to have duplicated entries in a table?
In this case, I would keep the single table and allow repeated song titles.

Lookup tables are used for finite sets (artist, status, city etc). Moving song titles to a lookup table will result in a lookup table nearly as large as the main table. If anything, artist should be a separate lookup table because this will be common attributes for several song entities.

A table will generally store an object or entity, in this case a song. The common attributes for a song can be moved to a lookup table, but song title isn't one of these common attributes. The same song title is usually a coincidence: you'd probably be better with "CoverOf" and "ReReleaseOf" columns to deal with these cases.

The fact of storing the same text in several rows isn't breaking any rules here because it isn't repeated text in the lookup sense

Also see: Proper Use of Lookup Tables