Curious pballard3....I use my Contour2 remote to order/play my Prime Watchlist all the time. I also add/delete items to the same Watchlist. So your issue of having random rentals when using the remote is terrible. I find that I cannot use my Sony TV remote to access any internet Apps. Since my HDMI is hooked to the COX Dvr, the TV remote cannot access shows passed thru by COX.
I also many times go onto the Prime thru the PC site to add to Watchlist and maintain the shows. When you use the PC Prime, do you also get random selections. Meaning, do you pick something and get a totally different show both thru the PC and Apps of the remote? Does playing the Trailers also get the wrong ones?
You also mention Showtime Apps are random...huh... shows you Remotely select get a totally different one. I go to my currently free Starz with no issue. Maybe your remote needs to be re-synced with your TV or the DVR needs hard booting.