Fermenter not accepting ejected universal cells

Is the Fermenter not accepting universal cells from ejecting blocks (like the item buffer)?

Here's my set up, from the front:

Fermenter(Liquid Fuel Firebox behind it) -- Semifluid Generator
Item Buffer (with ejector upgrade to Fermenter) -- Hopper to Item Buffer

The idea is to have the Fermenter have the liquid ejector going to the Firebox, and any extras get put in the unicells and ejected into the generator, which fills from them, drops the empties into the hopper, empties go into the Item Buffer, which then ejects to the Fermenter.

Is this a bug?

The bottom. If it needs to be the top, I'll try to redesign.