Red error: Key already exist when hitting a wall

Bug Report Template:

Bug Report
Expected behavior
When I hit a wall twice with a second distinct stack whose path is blocked by another wall, the move is canceled.

Actual behavior
When I hit a wall twice with a second distinct stack whose path is blocked by another wall, I get a red error. Upon checking the console, it says "Key already exists".


Steps to reproduce the behavior
This requires two players at war to reproduce:

1. Player A creates two walls (1) and (2), where wall (2) is behind wall (1).
2. Player B moves two stacks of units in a position where they can hit wall (1) but not wall (2).
2. Player B uses 1 of the stacks to move it to a distinct position, and then move it again to attack wall (2).
3. Player B uses the other stack to try and attack wall (2) while having wall (1) in the way.

Information:
Browser: Microsoft Edge
OS: Windows 11

Attachments:

Then fix it yourself g