I think that brings it to 4 confirmed cases on just this forum:
http://www.thorforums.com/forums/f8/...issue-808.html
I have not yet replaced the tail lights, but I have purchased new ones that I will install this spring as soon as weather permits.
I have confirmed (at least on the 28Z) that the plywood is localized to the area of the tail lights, and I suspect it is the same on your coach. But you have to waterproof the area. The link above is how I did it.