I’m well aware that the talent requires you to cast BOTH a Fire & a Nature spell to trigger the free Elemental Blast. It works with most combinations of such spells without problem. However, Earth Shock, despite being a Nature Spell does NOT count as one for the purpose of triggering Fusion of Elements. I have tested multiple times, and 100% of the time Fusion of Elements fails to trigger when Earth Shock is used either before or after Lava Burst. I have even tested to see if I was just too slow on the casting by using Flame Shock afterwards since Flame Shock dealing Volcanic Damage counts as both Fire & Nature. Casting Flame Shock after failing to trigger Fusion of Elements from Earth Shock + Lava Burst resulted in triggering Fusion of Elements every single time. Which can only mean that one of the two spells used prior wasn’t considered as Nature or Fire… Since using Lava Burst before or after Lightning Bolt triggers the talent with no issue, that leaves only Earth Shock as being incorrectly tagged.