Seed repeats start and end frame

[Dogway]

So I was using seed=17 because I like having some ground truth to tune settings from and noticed how in frame 15 and 16 the grain pattern repeats, only shifted up by a few pixels.
In order to reproduce the issue I had to scale up the source, so it seems the issue is also size dependent:

YUV444
BilinearResize(2780,1780)
AddGrainC(3358.593750, 3358.593750, constant=false, seed=17)

[pinterf]

Only at 17? Probably this seed number makes the pseudo-random algorithm to show its pseudoness?

[Dogway]

I'm not sure, didn't feel like frame skipping for a few hours lol
Seems to be a mix of the seed and resolution, so maybe backtracking it to code something could be hinted.
I chose 17 as a solid prime number for the randomness.