C4d Volume mesher not joining two objects



I am having trouble smoothly joining two objcects underneath a volume builder.

The aim of my project is to simulate mushrooms growing. In order to do this i have created a sphere and put it under a cloner with a dynamic tag. I have then created a tracer which is linked to the sphere in the cloner. This way everytime that the cloned spheres are moving in raection to the dynamic tag- their path gets traced. I then put the tracer as part of a sweep so that this appears as the “stem” of the mushroom growing and appearing as the mushroom moves up or “grows”.

I attached the sweep which makes the stem into a volume builder and there seems to be no problem, the volume is formed as the tracer objects appear in reaction to the spheres moving. However i can’t seem to get the spheres on top of these stems to properly join up in the volume builder with the stems. Every time i try this all the gometry seems to explode!

Hopefully someone has an idea of what could be going wrong.

Attached below is the c4d file for reference in case it helps!

Volume builder and dynamics problem.c4d (264.0 KB)