Hi Blackant Master Studio

I need to begin by saying that I hardly have a hope of helping you because I don't have Zbrush and I've only used the basics of CC3 Pipeline.  

What I hope is that you will get a reply from someone else if the thread stays alive.  I watched both videos carefully to see if I could spot something wrong. 

I looked several times at the steps you took and saw that you had mistakenly selected the wrong body part (fingernails) before replacing the mesh.  Then the time it 'worked' and brought in a new figure you had a figure selected from an accessory group.  I wonder if there is anywhere else in the content library you could have selected the figure to be replaced?  It looks to me that your figure from Zbrush has appeared as a new accessory.  Is that possible?

I hope someone with real knowledge can help.

I believe you have to press the 'All' button next to the 'GoZ' button inside zBrush, that should give the option to 'update mesh' instead of create accessory and such. Hope that helps! Let me know if it works

Try this: