Leaking water in corner of left back.

Yesterday I found a left rear corner had started to leak. Notice that a small 6 inch section came out of the rear corner seal. Found it before any real major damage done. Here is a few pictures.

Your pictures looked almost just like my camper. Mine may have been a little worse. Found the problem on mine about a month ago. I could not find the exact place where it was leaking so I caulked everywhere across the back of camper. Did you find where the water was coming in on your camper?

Found the corner molding was pulling away from the side and let the water in the corner. Pulled the molding all the way up and put extra screws in and lots of 1 inch weather vapor (monkey dong) to help seal the corner. Put new caulked everywhere across the back like you did Gator. Now waiting for the next rain to check for leaks.

My corner molding was pulling away. I thought that it was caused by water seeping in from somewhere on top causing the wood to swell and push the molding backward. The caulking was not sealed on the side from top to bottom on corner molding.
I had to remove the corner molding and some screws across the bottom to open the back enough to take out about a foot of wet insulation down the side. I then let the wood dry out with some help from a hair dryer. Put new insulation back in. Like you I sealed the corner (hopefully) real good and chalked everywhere I thought might leak. I am now waiting , so far so good. Definitely going to keep an eye on it. I hope yours is fixed. Good luck!!