When does Flammable Fumes become flammable

[Jakers]

When does the spell Flammable Fumes becomes flamable? There are a few different interpretations in our group of the phrase "One round after" and I'd like your inputs on the different view points and a ruling I'm considering making on them.

Flammable Fumes - https://2e.aonprd.com/Spells.aspx?ID=913

The disputed portion of the spell happens in the 2nd half which reads:
--
One round after you conjure the cloud, the gases loses stability and become flammable. If an open flame is brought into the cloud, or if anyone within the area uses a fire effect, the cloud detonates in a massive blaze that deals 10d6 fire damage to all creatures within it, and the spell ends.
--

Interpretation #1: The cloud becomes flammable at the end of the next Round. This would keep it consistent with how a dragon's Breath Weapon works when it has a recharge time of 1 Round. For example if on Round 1 PC casts Flammable Fumes it stays non-flammable for Round 1 since no round passed yet. On Round 2 it stays non-flammable for the same reason since the round. Finally at the start of Round 3 the cloud becomes flammable before anyone's turn starts.

Interpretation #2: The cloud becomes flammable at the end of the player's next turn. Reasoning being that a Round has gone by relative to the PC casting the spell. Round 1 cast spell, not flammable. Round 2 spell becomes flammable after casting PC's turn ends. This perspective views the non-flammability as if it were a status condition that auto decrements.

I'm thinking of ruling in favor of interpretation #1 for the following reasons:
1) The explosion damage offers no save for 10d6 fire damage AOE
2) This approach keep the decrement logic in Rounds consistent with other powerful AOE abilities that have a cool down like a dragon's Breath Weapon
3) If interpretation #2 were the case I'd expect phrasing like "becomes flammable at the end of your next turn" similar to many other actions are worded.

Any thoughts on these two interpretations? Any similar spells that work similarly?

[breithauptclan]

Jakers wrote:

This would keep it consistent with how a dragon's Breath Weapon works when it has a recharge time of 1 Round.

Wait. Where does it say that this is how a Dragon's breath weapon works?

I have always understood that things that tick down every round have their duration updated at the end of the turn of the person who created the effect. So things like Barbarian's Rage, sustained spells, breath weapons with a cooldown...

So yeah, I would run it with Interpretation #2 - it becomes flammable at the end of the caster's next turn.

[Aw3som3-117]

The last person in initiative is a pretty artificial thing, so I fail to see why that would be particularly important. In fact, I can't actually think of anything that specifically calls out happening at the start or end of a round irrespective of the thing that caused the effect, and I've always read "1 round" as 1 round from the point in which it happened, which will give everyone 1 turn as opposed to giving some creatures more turns than others based on where the initial effect was in initiative. Especially since you can adjust where you are in initiative at any time with delay.

Like, the person at the end of initiative can just decide they want to be at the start of the initiative tracker of the next round if they want to. It also creates a weird situation where rolling better for initiative can make it harder to coordinate with other players as they'd likely be unable to interact with the spell for 2 turns instead of 1, which sounds off to me.

[Jakers]

@breithauptclan and @aw3som3-117, thanks for your inputs. I reread the section on durations on nethys: https://2e.aonprd.com/Rules.aspx?ID=291

Spells with a duration in rounds decrement at the start of the spell casters turn. So sounds like Flammable Fumes become flammable at the start of the caster's next turn.

So interpretion #2 is correct with the adjustment being its teh start of the turn not end.

Thanks again for your help!

[Errenor]

Jakers wrote:

@breithauptclan and @aw3som3-117, thanks for your inputs. I reread the section on durations on nethys: https://2e.aonprd.com/Rules.aspx?ID=291

Spells with a duration in rounds decrement at the start of the spell casters turn. So sounds like Flammable Fumes become flammable at the start of the caster's next turn.

Yes, "until start of the caster's round unless it is said to last until the end of their round" is more consistent in general and with the rules.