In EPOE, there are some annoying Inconsistencies. Upgrading Eyes, arms and legs require first a basic prosthetic ingredient, then a bionic to finalize the Advanced counterpart of eyes, arms and legs.
E.G. "Light receptor" @ Simple prosthetic workbench is needed for the bionic eyes @ Bionics workbench.
E.G. "Simple prosthetic arm" @ Simple prosthetic workbench is needed for bionic arm @ Bionics workbench

I.E. Bionic ears should require the cochlear implant to craft them and the Bionic spine should require some basic prosthetic counterpart

Any chance we can take a look at this?