Yes, I also noticed this is a very old thread.
But to comment for the sake of others........
We bought this motor home pictured below, brand new in 1983 and sold it in 2007. Over the years, it developed cracks exactly like the OP shared, some formed right away. While under warranty the first year, I called the manufacture who said the cracks were only cosmetic. They were willing to fix them for me but said they would likely return, so I did nothing. I was glad I did nothing. The rig was fine (with more cracks) even the day we sold it 24 years later. The patchwork would have been ugly compared to leaving it alone.
So my advise is to do nothing.
![](https://live.staticflickr.com/3527/3729396233_56dba3b92a_z.jpg)