Open base mesh project. (At this point export to Zbrush works fine.)
Navigate to the Actor Project Templets then select and apply Head Morph Avatar preset_Head_CC3 Base Female. (Export to Zbrush still fully functional)
Now navigate to Avatar preset head and select and apply a trail Morph Avatar/preset/head_Essental Morphs_Asain Female(Trail) You will get the CC3 Water Mark. Now undo the Morph by hitting Ctrl z. (The Morph is gone now but Export to Zbrush no longer works and you get "Needs export Licence" error)
Same bug now diffrent senario.
Navigate to the morph tab and apply a few standard morphs. Morph_Actor_Full Body_Bodybuilder/CC1 Base Female/CC3 Base Female. (Export to ZBrush will work just fine.) Now apply trail Morph. Morph_Actor_Full Body_Body size Now hit CtrlZ to undo the trail morph. (Now Export to Zbrush no longer works!)
You can not even hit the "Reset" button that will fully reset your model, still, Export to ZBrush will not work. The only way to back out of the trail morph is to zero out the morph. ( Type 0 into the parameter slider and hit enter) If you have moved past any trial morph and even once used Ctrl z to undo you can no longer export to Zbrush and because resetting does not work you must start all over by reloading a new base!
I have attached screenshots of this issue as I have found it.