Assume you're referring to bonus RDMs for being 1P. This is normal and has been the case for quite some time. It makes no difference if it is or is not a codeshare. There are varying rules for mileage accrual on all star alliance carriers (UA and US included), which can be found in this thread (via the UA FAQ thread):

http://www.flyertalk.com/forum/unite...y-partner.html