The razing of the Missile Boat production centers involved a string of surprise assaults orchestrated by Grand Admiral Zaarin, a defector, who commanded forces against the Empire's Missile Boat manufacturing plants. This resulted in the mandatory return of all deployed Missile Boats.
Due to the annihilation of the manufacturing plants, combined with combat attrition during various operations, and the unrelated pilfering of the Missile Boat experimental model Sealion by Rebel operatives, along with its subsequent recovery, Emperor Palpatine mandated that all operational Missile Boats be brought back to base until the Rebel Alliance was crushed at the Battle of Endor. Yet, Palpatine's demise during that pivotal battle meant the recall order was never rescinded, effectively ensuring the Missile Boat's permanent retirement from active duty.