Steps to fix (until Ryan patches it):
1. Go to the following folder (On windows, not sure the exact path for Mac):
C:\Users\yourusername\.spawnpk-data\loadouts\
2. Delete the order.settings file
3. Start the client, it should load once
4. Log into the server and create a loadout, doesn't matter what's in it
5. Try closing and re-launching your client, it should now work every time