Lol - I hate those 'I shoulda just left it alone' moments when working on cars.

Like Ant said, fluid changes can often expose leaks. It can shift build up, dry seals and as I mentioned - the newer, thinner fluid can start to push through the tiniest of areas that maybe the older thicker fluid couldn't.

I'm not familiar with that end of the system so probably can't help much more other than to tell you to keep cleaning/driving/repeat until you locate the leak. At least you can start researching the remedy once you've diagnosed the fault area.