AA unit firing from Rain /Fog hexes

[taffjones]

I am playing a PBEM game challenge number 166498

In China attacking Nanjing and my opponent moved a AA unit behind the unit defending Nanjing, on my turn the weather was clear over Nanjing but the AA unit was in a hex with rain and fog.

I attacked with infantry units and then Carrier air units, only to find the AA unit was devastating my air attacks 0.2 or more, the defending unit had no AD or entrenchment.

Is this a one off series of bad luck dice rolls or a bug?

Should a AA unit in a hex with rain and fog be able to inflict such bad results on aircraft attacking units in adjacent clear weather hexes?

[EarlyDoors]

Hell yeah