I used Asteroid Miners Luck enhancer which guarantees 100% reroll. I ran SlouchO map 5 a couple times to kill the boss, and I found that sometimes when I get a purple (epic) item, it does not say in chat that i rerolled for better loot. This means that when I dropped purple, it was supposed to reroll but it didnt. When I hear experiences from others who dropped them in the past year, they say that they dropped without reroll.
Is this supposed to happen?