How often do you flush the heater tank? If not often, or it's been a while, it could be calcium build up. If there's enough mineral sediment, it will make loud banging/popping noises due to steam trying to escape the sediment/build up (or even one big one). That would explain the extra cycling, too since the sediment causes inefficient heating and can cause overheating which can damage the tank. Assuming the tank isn't damaged, I'd flush it and replace the T&P valve anyway. Just because you can "flip" the mechanical lever, doesn't mean it's functioning properly @150 degrees as it's designed. You don't want that thing failing.
Although, the way you describe the noise...I don't know. Then again, everything seems amplified while you're in a tin can. Maybe there is in fact a small, seepage as a result. You can still have a very slow drip and not have the pump cycle.
Edit: If there's water where there previously wasn't, that's kind of a no-brainer.