I keep returning to families to find them dressed like idiots. Help.

Ever since I bought Seasons, my sims have begun dressing up in crazy randomly generated outfits which I have not set for them at all. For example, I will be playing family A and they will pass through Winterfest. I will then go to play family B and everyone is dressed up in some random outfit. It always seems to happen when an event has come and passed recently. It's so annoying because they often don't change immediately and a sim will come over to the house dressed in a Christmas dress when Winterfest was a few days ago,

How do I stop them from looking like they got dressed in the dark inside a drama prop and costume cupboard? They end up looking like the townie in the infamous "My Townies vs My Sims" meme.

Also the same for my Spellcasters. I understand that when they go to the magic realm they get a "Spellcaster" outfit featuring RoM clothes, but can I stop that or at least find a way to set a RoM outfit for them?