How do prophecy requirements generate?

How do the CoF prophecy requirements generate? Lately I’ve been noticing a few weird things:

  • I’ve been getting a lot of high difficulty ones (T4 dungeon boss, 200+ corruption monolith events, etc) on a character who hasn’t even reached empowered monoliths. Meanwhile when I was playing my old character that was already around lv 100, I was getting comparatively easier ones.

  • Requirement-reward pairings are way out of wack. Just an extreme example: Within a single constellation offering, I was offered 2 different prophecies with the exact same reward, but one was like “kill x number of rare enemies in any monolith” and another was either kill a T4 boss or do some 200+ corruption monolith boss, I don’t remember. It’s weird that the difficulty doesn’t seem that connected with the reward.