Static mesh foliage scaling doesn't work

This or uniform with all the values set as 1 produce the same result.
It’s spawned through a PFS, I’m resimulating every time.
There is a very small variation but it’s barely noticeable and I have no idea where it comes from, definitively not the ratio I have specified here.

I found Growth / Procedural scale, that kind of work, but it’s like it spawn most instances with the min or the max values, rather than something random in that range.