Nike Air Pegasus+ 27 GTX - First Impressions

I will be participating in the OXFAM 100k Trailwalker event this summer. I finally settled on the Nike Air Pegasus+ 27 GTX in mid February. I have been doing a lot of training in High Park and noticed that after about a month, the soles started separating from the shoe! I took them back to The Running Room where I purchased them, and they ordered a new pair for me. I was reassured that it was unusual that they fell apart like that.