Okay, it turns out I was mining with two different addresses. .00012807 was received via 1Q68UdKBYgBVy7h4gAAXcipaoBPeoJZrXQ—I was mining with this address for a very short period at the very beginning (no more than a few hours). Then I switched to 1yrraLgmRZ1fbgtz2BSVXcWVrJnH785QZ and used that one for the remainder of the entire period.

So I got the payment via 1Q68UdKBYgBVy7h4gAAXcipaoBPeoJZrXQ, but not for 1yrraLgmRZ1fbgtz2BSVXcWVrJnH785QZ.

Hmm, I'm actually 1yrraLgmRZ1fbgtz2BSVXcWVrJnH785QZ—I received exactly .00012807 BTC on this address.
And indeed, I was mining during the entire last several days, as far as I know.

Edit: I just checked, and it turns out I very briefly mined using 1Q68UdKBYgBVy7h4gAAXcipaoBPeoJZrXQ at the beginning. This was for a very short period (no more than a few hours or so), then I switched to the address I mentioned above for the remainder of the time.