Steam achievements?

[Adagio]

I have noticed a new problem with Steam achievements

It said two days ago that I got the Where's the Biathlon achievement, which is pretty impressive considering I was playing as Kamehameha, who as far as I know is not the leader of Denmark

One of my enemies was Denmark, so I assume I got this achievement because Denmark entered the snow tile with the ski-unit

I have noticed problems like this before. I remember I got the Barbary Pirate achievement after I got 3 Barbarian naval units


I'm not doing anything I can to get all achievements, I do prefer to have fun, but it's still interesting to look at

[Boracks]

Were you friends with a military CS? I've noticed that they will occasionally gift you a unique unit from another civ, so it is possible you may have gotten a ski infantry and then triggered the achievement.

Long odds I'll admit but possible.

[Adagio]

I was ally with all other CS's, but none of them gave me a unique unit and even if they did I never would have walked around in the snow with it. I also noticed that I also got the achievement for winning as Denmark, but the game I was playing, Denmark won

[CerberusIV]

Not a new problem. I got the Barbary Pirate achievement ages ago (I play a lot of archipelago maps) - except I had hardly played the Ottomans up to that point and they were an AI civ in that particular game. So that achievement at least is bugged.