I was stuck and pissed off the whole last week also. Everything dropped 265 for the longest time, it was frustrating. So just two days ago I got bored and went out to Nessus and found all the Regional chest, the gold ones, and the lost sector caves. To my surprise the light level drops became slightly higher, it was slow but it was getting higher. I don't know if it has to do with those things but like I said, for me to get to 279 from 265 in two days, I had to go play the game as intended and of course some lucky drops with it. Give that a shot on Titan this week if you get stuck again. But I doubt you will , once you hit 280 you can put those purple mods and jump a lot of light levels. I'm no expert but this was how I overcome 265. I did a lot of heroic public events also I think I got two or three exotic engrams from them, one of them I failed a HPE and I still got an exotic engram.