I changed the filters on my AC this week. It's ultra humid in Houston, so the amount of condensation that comes out of the air is incredible here. It's so bad that if the AC in your house has its condensation drain clog, it could literally flood your house and do a lot of damage.
Anyway, I think I know why our cars are so susceptible to the odor in the AC. I noticed the filters are sitting right on the surface of the evaporator coil, so my lower filter was damp when I removed it. I don't think every car has the filter right on the coils like that to get wet every time the AC is on, so that may be why other cars don't have the issue in the same conditions.
Not much we can do but change the filters more frequently. I don't think Tesla''s software update to run the fan to dry the coils is enough to dry out a soaked paper filter. So the mold will win in humid climates.