Hello, thanks for using lyrik

Each songs has more properties than title and artist in online database, they are: duration and file-size. But the client side only title & artist are used to search in cache (simple cache).
So you can use "File cache" (Lyrik > Preferences > Last option icon > File cache) OR you can save both songs lyric files once (using each file name).
It should work fine, but if don't just report here ;)
Thanks again,
Willian