I looked carefully around the trans to see if the fluid could be coming down from there, just to make sure. I looked for a defect in the pan too. Nope, it's coming out of between the pan and the trans through the gasket area. Above the pan it's dry.

I've come to the conclusion that it's because the pan bolts keep coming loose. Since no one answered, I guess it's the Blue Threadlocker I'll try. Red seems a little much.