That's certainly possible, but mathematically unlikely when I drag 5+ in a row with the same exact hp, then one or two with different hp, then another several in a row with the same average hp. And with different mooks. And not once or twice, but frequently. Possible, yes, but it seems highly unlikely. Try to get the exact same number 5 or 6 times in a row on a 4d8+15 roll.