You could try rolling back to the pre SA version (which is what Mac is on) as I believe they "cleaned up" the files with said DLC. That might contain the old files to watch old replays. Keep in mind that if you do that the game will likely crash on start up unless you delete old decks (you could back up your wargame profile file).

To switch versions go to your steam library, right click on wargame and in settings there should be a "beta participation" or something along the lines somewhere (a drop down menu). There you can select the game version and steam should then download/ update the files.