Well if your main jack stands underneath were to sink or fail, (or if you just retracted them without removing the slide jacks) the weight and angle on your slide jacks would certainly do damage.
Just my opinion, no data to back it up.
2010 Jayco Eagle 324BHDS "Eddie"
2006 Dodge MegaCab 2500, 5.9 CTD with Manual Trans. "Rambo"