Sometimes PlayStation's platinum trophies are easy to come by. Other times, they are downright impossible to procure. Some trophies make you regret even earning them, but others are a little... scummy. Take Destiny 2's platinum trophy, for example.
Apparently, someone posted on Reddit that Bungie locked Destiny 2's platinum trophy behind DLC, but that's not exactly the case.
But what may be a reality is that one of the trophies/achievements, namely "The Prestige," have been essentially "shifted" to the new DLC, Curse of Osiris. According to one Reddit user, the trophies that unlock when completing Nightfall or Raid aren't exactly locked out, but with the release of the DLC, they've made the "modes harder to match the increased power of items dropped in the DLC."
In other words, if you don't have the DLC, it will become much harder for you to obtain and complete the trophy. Essentially, you'll either need a carry from DLC owners or extremely favorable mutators on Nightfall.
I think, if anything, it is a bit of a bug, but if Bungie keeps it in, then achievement hunters will remain understandably upset.
As for any full confirmation on the matter, we will have to see. But so far, the DLC has been a little... messy.