Scatter-Not showing full count Tweet

[Exactly13_1]

I have built a scene with about 15 scatter objects and in total it is scattering about 30K objects. All works as expected so far.
I then either merge or paste the scene into another scene (I tried a few different scenes...same result) and some of the scatter objects (ones with a lower count) behave as they should but most of them only show a small amount of objects even though the counts have not changed.
I can reduce the count and then see it working (with a lower count) but as soon as I go higher it stops showing the extra objects. It is like there is some sort of limit on the count but I know this is not the case as it works perfectly OK in its own original scene.

Any ideas?

Using 2021.1.5-R4
Windows 10
RTX3090