My statement was based on the explanation of the abilities on page 15 of the English rules. Here is the rule for the board you've mentioned:
After the player performs the “Build 1 Wall” Court Action, or the “Recruit 1 Official” Court Action, he may take 1 value-1 Unification Marker of his choice from the general supply. If he cannot because the supply has no value-1 Unification Markers left, he gains 1 VP.(page 15)
All of the player-board action explanations indicate that the effect happens "After the player performs ... [a particular] ... court action."
It might have said "After a player places a wall token on the board" the effect fires, but it does not. The effect is triggered by taking the court action, not by placing the wall. At least that's my reading. Did you see something else in the rules that suggest this is not right?
(edited to get the quote right)