Not sure where the latest typo bug thread is, but here are 2 more:
“The explosive scales”, should be, “The explosion scales”
You seem to be confused as to whether you’re talking about multiple explosive ground (the second two underlined words) or a singular explosive ground (the first). The sentence should either read
Volcanic Orb leaves Explosive Ground as it travels, which explodes after 3 seconds, deals fire damage to enemies within its area of effect
Volcanic Orb leaves Explosive Ground as it travels, which explode after 3 seconds, dealing fire damage to enemies within their area of effect