FWIW, I've never seen an RV that you have to crawl under the trailer to access the dump pipes for the rig. They should stick out (flush with) the street side of the trailer.
My best guess is that there was some damage done to the trailer (caught the "stock" system on something) that cracked the original pipe and they just glued on a collar and capped it up past the cracked area...
My 2 cents, your mileage may vary...
2 Cats; J-Lo and Ragamuffin :R
2014 Thor Tuscany 40RX DP
2011 Ram 2500 Longhorn CTD HO
2011 Keystone Cougar 318SAB (now gone)
2008 FunFinder X 210WBS (Sadly gone)