Helminth Cyst not growing on second Nidus

[(NSW)MiiMike]

Hello after extensive searches I haven't found this specific bug answered. Some background:

My first Nidus was purchased from the marketplace via Plat. leveled to 30 and inoculated in the helminth room prior to unlocking the helminth system. 

This was before I was aware of the Helminth charger. Eventually this first Nidus was subsumed via Helminth.  

I built a second Nidus via in game grinding, leveled to 30 with the plan to use it to make a Charger. This was leveled prior to unlocking Helminth system. 

There was no option to infect /inoculate this second Nidus via the Helminth room. 

I've since unlocked the Helminth system but would still like a Charger. 

It's been several months since I built this second Nidus and no Cyst has grown on it.