Did you ever connect to Eliguis (Luke-Jr's) pool. It doesn't usually distribute payments unless you haven't connected in which case it will payout whatever is left in your account.
Other than that it could be someone transposed a character in their bitcoin address and it happens to match yours.
Or it could be a bitcoin address clash even though the possibility is statistically minute.
I've connected once to Eliguis, found that the balance on coin-explorer was actually going backwards so didn't bother with it any further - that's probably what happened. Thanks.