Fire Skill Question - Persisting flames

The description of the Persisting flames goes -

Executing blast finishers on fire fields grant fury. Fire fields last longer. Create a lava font when you go down.

Fury (10s): 20% Critical ChanceDuration Increase: 2s

My question is about the combo part, whenever I try it either with lava font and Eruption or Arcane Wave, which are both blast finishers as described.The fury I get last only for 2s instead of listed 10s in description and i hardly even manage to use another ability that would befefit from the buff.
Have I misread it and the 10s in description is just some description of fury buff unrelated to this skill? Am i doing something wrong?

10 sec of fury, 2 second of improved fire fields. It seems like a bug, would be great if more people can test it and report in game.

Ok so I found the reason, I was testing my skills at special force training area and apparently it doesnt work there but anywhere else it does. :)