Rated below 1500 in rapid, but Lichess doesn't let me play in U1500 Rapid Arena - why?

My rapid rating was above 1500, but dropped with the last few games. I thought I'd be able to participate in U1500 Rapid Arenas again, but when click on the Arena link, Lichess shows "Rated ≤ 1500 in Rapid!" in red, as if my rating is still above 1500. What's going on?

Sorry, you must be at under 1500 for a week to play in U1500 arenas.
The rules for other rating restricted arenas are analogous.

I see. Thank you.