In the scene between Gable and Beery at the rail, the camera angle reverses position several times, switching from an inboard and an outboard position, but the two actors never switch positions, Gable staying always on the left and Beery always on the right.
Although Harlow is completely drenched from head to toe in the storm, she appears in the scenes immediately thereafter with her platinum wig back in place, perfectly coiffed with every hair, wave and curl just exactly as before.
During the storm when Jamesy MacArdle grabs China Doll and swings her around in his room towards his dresser at about the 48 minute mark, her dress strap comes down revealing what appears to be her bare breast. She quickly lifts her strap and continues.
The goof items below may give away important plot points.
Gaskell tells Davids he has only five seconds until the Mills bomb (British-made hand grenade) goes off. Actually, the standard No. 36 Mills bomb used after WWI had a seven second fuse. (This was reduced to four seconds in WWII when it was determined seven seconds was too long, allowing the enemy to avoid the grenade, or worse, throw it back.)