At the beginning at the checkpoint when it is supposed to be raining in some shots it clearly is not.
The "Allied Checkpoint" sign at the beginning of the episode shows four flags: UK, France, West Germany, and USA. By international convention of the time, there should have been no West German flag on that sign, only the flags of the three Western Allies.
There is major grammatical error in the German writing on one of the signs in the beginning of the episode. Instead of "Sie betreten den DDR" it should correctly read "Sie betreten die DDR".