HA! For some reason, I thought it was linked to the timeline, as I don't remember manually updating it before (though I obviously must have). Thank you, that would have driven me crazy!
At first I thought it was because your "Date green card received" in the ROC section is blank, but I've posted since updating mine today and it still shows as "Adjustment of Status (pending)" when I post. If I figure it out, I'll let you know!
