I've the latest version but an old samsung galaxy and only saw the black box in one Rolling Stone song but couldn't find more songs with info. Btw, I wasn't able to read the song info, tapping/ clicking the black box didn't work.
Just tried reinstalling but it didn't fix it for me. Still no Behind the lyric. I tried multiple songs in the Behind The Lyrics: Hip Hop playlist. I'm on android and am a premium user. If anyone knows a fix, let me know!
Keep in mind not all songs have Behind the Lyrics, so it's possible you're choosing songs that don't have their lyrics available. Also, there a chance you won't find the whole song's lyrics, but you'll find more info about the song.
Have you tried playing different songs in order to see if it works?