Unable to join <1700 Bullet Arena despite meeting criteria

I am currently under 1700 in Bullet and do have >>20 rated games, yet am unable to join a <1700 Bullet Arena tournament - the "Join" button is disabled.
Is this expected or a bug?

thanks for the clarification, makes sense now

Well, once my rating dropped and I was <1500. Yet I was able to join an <1500 blitz arena so I don’t think that’s entirely true @AngelaRoss