Sorry I don't have much to go on here but... I lost the Neuro core somehow. I got it early on and it sat in my inventory. Later I got the automated ship skill and put it in a ship in the fleet screen to see what it did etc. From here I am not 100% sure, but I think I put the ship back into storage at a settlement. Hours later when I decided to actually use some automated ships I couldn't find the core.
I think when I stored the ship it was in, the core just vanished, but as I said I don't really remember if I removed it first etc.
I can't find it any where else. I have searched my save file, there is no instances of 'rat_ai_core_special' and 14 for 'rat_neuro_core'. None of them seem to be a core for a ship, but I don't know the save files that well.
No idea if this is a bug, normal behaviour, or something else, but figured I'd report it anyway.