upper half seal substrate material?

I have discovered a potential problem on my 2001 model 2619 that I'd like to ask the group about.  :-/

The composite wood substrate to which the lower seals are attached in the upper portion of the manor, are all cracking, and in some cases, in the corners, where staples were put in, have disintegrated completly.

Has anyone else noticed this?

According to Jimmy Davis at TM, prior to 2002, they used this composite material as the substrate material for mounting the seals.

I've noticed several cracks both vertical and horizontal in this composite substrate board material, mostly below the seals, and in between screws. The material is dry, has no discoloration. Looks like original material - a pale pine look, and is exhibiting no signs of moisture or dry rot. Just cracking. Just appears to be losing it's structural integrity by cracking. It appears almost brittle.

1) How serious a problem is this?
2) Has anyone else had this problem?
3) Has anyone replaced this substrate material?
4) If replaced, what did you replace it with?
5) How hard a job was it to replace the material?
6) If not replaced, how did you repair or reinforce it?

I thought this material was a composite plastic a first until Jimmy told me that it is actually a composite wood material.

Am interested in any feedback. Thanks folks!

Gregg