Did some more investigating and then completed what I believe is the repair on the above leak.
When I looked close at this problem, what I thought was the deteriorated polyurethane caulk, I found it was not lifted as I suspected.
On further digging, I could see that the water should not migrate to the inner channel. The OEM has included two drain holes, that are seen from the outside lower window frame, and if not blocked should drain any water from the channel.
The problem that I found was, the placement of liquid rubber plug over the frame joint that makes an effective dam, allowing captured water to only drain from the hole on that end of the window frame.
On my window, someone? had deposited another gob of white caulking in the front portion of the channel, blocking the water from draining, and causing it to flood over to the inner channel.
I removed the slide window and cleaned the area and reinstalled and am confident that this problem is gone.
The slide window can be easily removed by pulling out the upper slide rubber material, and the window lifts out.
The lower slide rubber was embedded into the liquid rubber caulk mentioned above, thus not allowing water to drain.
When you have your air hose out, blow out the drain vents from the outside. This will move any minor blockage that is in the channel and maybe allow it to drain better.