[svacko]

Yes, I've experienced a few poeple drilling the additional drainage holes on the bottom of the outdoor unit, when they experienced similar problems not having a "nordic" unit. With the nordic unit I mean the features mentioned above - heated compressor and the heating condenser vane.

Though, if it's snow blowing directly inside then I think creating some barrier or add additional shielding of the outdoor unit is required,so that you minimize the chance of the snow DDoS-ing the unit (note: check your unit's service manual for the minimum free distances from all sides of the unit, especially the front one that is the most important to be kept enough free space).