Were you hacked? Someone got access to my account and transfered 0.3 LTC to LS12fGBGyDoB4FqNABVawUymXWuVBhc4rF. They also created addresses for DOGE, PPC and FTC which I was not mining. I'm pretty sure they had no access to my PC.
No, I protected withdrawal with Google Authenticator on my phone. But I forgot to save secrete key and broke my phone. Therefore, I can not change my setting on withdrawal address. I also want to try mining Feather Coins but could add my wallet. If you have access to change withdrawal address, do that and secure it with Google Authenticator. But don't forget to save secrete key (as I have done 
) in case you lose or break your phone. Good luck mining. 