1. this is the first time ever where denoiser just doesn't denoise but frame before it denoised fine.
Almost similar frames jsut phoenix smoke moves a bit
2. And another strange thing with frame 452 is when enabling AI lights denoiser starts working except octane viewport render time is 50 seconds, regular rendering is over 4 min. So some bug with AI lights
(it still doesn't denoise with AI lights off)
UPDATE: problem 2 happens with all frames. Very slow render time with AI lights