
Fuzzypaws |

Metatheurgist is incorrect. The example of play provided on Page 11 of the CRB shows the burn damage being applied immediately at the time the critical hit is rolled.
Also worth noting, that same example clarifies that the burn damage is only rolled once at the time of the critical hit. It then becomes static ongoing damage at the start of each turn until it is put out. If you roll a 3 for burn damage, it will be 3 every turn, you don't reroll it each turn.