Reproducible 100% of the time, his second cast of Battle Dance is supposed to be mana-free but if Rakan is below the mana amount required to initially cast it he cannot cast it a second time even after casting it for the first time.
Yepp. It sucks.
Seems like a recurring problem with mana costs for spells that get a free cast. I don't know if Lissandra's old passive suffered from this, but Swain's old ult definitely did in old URF. Since the mana cost increased steadily, it would shut off the ult once the mana cost was greater than the total mana pool, even though URF spells were supposed to cost no mana. They did fix it after the first couple of URF iterations, but apparently they didn't keep this in mind when creating new possibilities of mana-free spellcasts (I think Rakan was created after Swain's ult mana issue was fixed on URF).
