I've had weepy ones. I think it happens if you have a pocket of unmixed stuff in the batter. Or in my case it was a bit of sugar that was on the top of the paddle and fell in.
When I was spooning in the mix I noticed it and tipped it in the patty pan anyway. I was a bit scared of overbeating so I mustn't have mixed it enough. I have also started giving the bowl a good scrape down, stopping the machine and getting in under the whisk.

Overbeating was the reason my cakes used to suck lol! I've recitified that now