Replays don't know when the player had used the DSU option, so [filter_vision] can produce different results when a replay is played.

For example, the player might toggle DSU on, then trigger an event which checks whether enemy unit X is visible or not using [filter_vision]. The result can be different when playing back a replay, because the replayed move might uncover enemy unit X whereas the in-game action won't because of DSU.

Sapient suggested that one approach to fixing that would be to record all togglings of DSU in the replay data.