Detecting obsidian + cobblestone generation

I am currently developing a 1.8 Duels plugin (my first actual game) and I'm trying to make it so that lava that gets turned into obsidian will disappear after 5 seconds. I have tried using BlockFormEvent (the suggested event for this action) but it doesn't actually get triggered at all when obsidian/cobblestone is formed. How can I detect said generation?

 

@imxforce
It should trigger, as the example you mentioned is listed

Code:Java

Examples:
 
Snow forming due to a snow storm.
Ice forming in a snowy Biome like Taiga or Tundra.
Obsidian / Cobblestone forming due to contact with water.
Concrete forming due to mixing of concrete powder and water.

Are you sure you registered the event?

 

Yeah, I registered the event and I've also got @EventHandler above the event.
Problem is the event is literally not getting called at all when obsidian/cobblestone forms.

 

Show us what you have so far