The Waverly Ring Affair - S2-E19
Visible crew/equipment: When Solo enters the scanning room, the shadow of the boom assembly sweeps down the wall on the right side of the door. (00:07:40)
Visible crew/equipment: The shadow of the camera is visible as Captain Brent walks the Seaview's corridor.
Flipper and the Bounty - S2-E13
Visible crew/equipment: After Bud wakes up all alone in Bligh's cabin, he soon realises all the doors are locked. Then, just as Bud rushes over to the stern window (particularly the second time), a seated crew member is visible at the bottom right corner of the screen; we can see the movement of a leg and two hands (so, it's not a mannequin).