Shock effect cannot be extended via Stormfire support if applied by shocked ground

I was using gathering storm with stormfire to shock bosses for me, and using incinerate to actually kill the boss. Occasionally, when the hit of gathering storm itself shocks, that can be extended by stormfire.

Duration of debuffs from ground surfaces is indefinite. You're shocked while standing on shocked ground. When you leave it, the debuff is removed. Such duration is not subject to expiration.

Simply put, expiring occurs when the debuff timer ticks down. While an enemy is ignited, Stormfire tells shock to stop ticking down. Due to how ground effects work, their debuffs don't tick down.