does vex apathetic stun gear that ori turns into the unit the turn become units

No — Vex, Apathetic won't stun it. Vex only triggers when an opponent plays a unit, and a gear that Lady of Clockwork turns into a unit gear wasn't played as a unit — it was already on the board and simply changed characteristics.

The distinction matches the token precedent (FAQ #10054): things that are played fire Vex's trigger; things that merely become units, or are created/put onto the board, don't. Nothing in that transition goes through the Play process, so no "opponent plays a unit" event occurs and no stun (or "can't move it this turn") is applied.

Two caveats worth knowing. If the same card is later actually played as a unit — e.g. a card with the Unit type being played from hand — that is a play event and Vex does trigger. And the transformed unit gear can still be stunned by other effects like "Stun a unit," since Rule 423.1 just cares that it's a Unit on the Board at that time.

This is my interpretation based on Vex's trigger condition and the Play rules; no official FAQ exists for this specific interaction.