Coalesced Corruption Cleanse bug

Hi, Game crashed during corruption boss map to cleanse the area and now the boss is gone and i can't cleanse the area. Help please

Not a bug. If the game crashed, you should still log back into the same map. If the instance crashed, then it counts as a fail and the area can no longer be cleansed. Find another Nexus to cleanse assuming you want to run cleansed maps.