This does not include known issues such as the experience gained suddenly disappearing, etc. These are additional notes after playing with the system.
Summarized as bullet points:
After installing forma, you cannot select a secondary energy color, unlike every other single thing in the game
Unlike every other item, you cannot equip ephemeras on necramechs
Necramech customization feels underwhelming, no armor, aforementioned ephemeras, etc
Necramechs have no enemy radar or vacum despite having a pet that has animal sense, fetch or vacum
Necramechs cannot pick