Question on Lyric FAQ

https://rekordbox.com/en/support/faq/lyric-6/#faq-q50250

Can somebody explains what is meant with this sentence

The duration (track length) is sometimes different from the original because of intro-edit, etc. In this case, please blank the duration and acquire lyrics.

I'm trying to add lyrics manually as Rekordbox can't find them automatically. But have no clue what is meant with 'please blank the duration and acquire lyrics'.