[519.E82]

I have 2 cars, my 08 128i and my winter beater. I always ran one of those 12v cig light air purifiers in the BMW and now that its winter i switched it to the beater. For the little while i was driving both cars i noticed the BMW has kinda like a tangy mold smell to it thats very unpleasant but dissipates quickly if i drove with the windows down but always comes back. any ideas?

Edit: is it also worth mentioning my AC is only cold on the passenger side and gets only cool on the driver