Under Alchemist Infused Reagents it has
As soon as you make your next daily preparations, your infused reagents from the previous day’s preparations are instantly destroyed, and nonpermanent effects of your previous day’s infused items immediately end.
The king's sleep poison has an onset and each stage duration of one day. So if this poison was crafted using infused reagents, does that mean the dose becomes destroyed before it takes effect? Or does the act of it having been consumed cause it to become permanent? What if I had started a forest fire with an alchemical fire bomb, would the fire go out when the alchemist does their daily preparations?
For poisons or other things with longer effects I will have to be careful to make sure its worth it. But if I can start fires that will automatically go out the next day, that could be an interesting ability.
Best Answer
King's Sleep
Generally, poisons with an onset of a day or more would not a good/viable choice for infused reagents. The rule is "nonpermanent effects of your previous day’s infused items immediately end." Most poisons have a maximum duration and are therefore the effects (everything below the line in their statblock) they cause are not permanent. However, in the case of King's Sleep, it has no maximum duration and is therefore (theoretically) permanent.* Because of this, the effects of King's Sleep would not be removed by that clause of infused reagents.
*Permanent is not defined in game terms so we are left to the dictionary definition "lasting or intended to last or remain unchanged indefinitely." Clearly, King's Sleep is intended to last indefinitely (Fortitude Saves nonwithstanding).
It could be argued that the only time things are permanent is when there is no "passive" way to end the effect. E.G. permanent blindness exists but can be removed by restore senses/sound body (remastered), but anything that allows a Save is not truly permanent. If that is how a GM is running their game, King's Sleep would be ineffective if wrought from infused reagents.
Forest Fire
The effect of Alchemist Fire is "The bomb deals Xd8 fire damage, X persistent fire damage, and X fire splash damage." If your GM determines that damage is enough to start a fire, that becomes an Environment (or possibly Environmental Hazard) that is an effect of that damage (not the bomb). Once the magic/pseudo-science is done, anything left is "real" fire. The continued fire would be, if anything, an 'effect' of the trees being on fire.