I have the '14 28BHBE. We lost one of our halogens on our second trip (IIRC), lost another not long after that. I don't know what caused them to go so quickly, but I replaced them and immediately went on the hunt for LED replacements. I've also had problems getting the pins lined up just right, give the bulb a wiggle or even flip it around and see if that works. Otherwise, you might want to pull down the fixture (not hard, just 3 screws) and examine the wiring in the back...
For the halogen fixtures above the dinette and sink, these are my favorite so far:http://www.amazon.com/dp/B00EC70UN4/...I3A9GF72Q5TJDI
They have the closest match to color and brightness that I've found so far for those lights.
If you're replacing halogens, make sure NOT TO TOUCH the glass on the new bulb, the oils from your fingers could be causing this blackness and premature burn-out. Otherwise, replace them with LEDs and worry no further...
My pair of pennies...
2014 Jay Flight 28 BHBE
2015 RAM 2500 6.4L HEMI, Tradesman 4x4, 3.73
Blue Ox SwayPro (BXW 1503)
Upgraded from an REI internal frame backpack and a Eureka 1/2 dome tent!