Trebuchet on fire, can't ligh the signal fires

[Rékaaaaa]

I'm tryna complete the Burn, baby burn challenge in the lost city, I have 3 signal fires already on fire, but the second trebuchet caught on fire too. I reloaded the checkpoint several times tried (I think) everything but it's still on fire. Please help.
(My last save was at 87% and now I am almost done at 97%)