Important reroll/leaderboard questions

[Misfit]

I farmed 50k points in the blizzerax map and looted one mythic item but something seems weird; numerous times I looted elite L110 items without rerolling (like I didnt reroll a pink into the elite). What’s weird is that these items didnt reroll into mythics even though I have over 100% reroll/luck. Before this event, in any other map I played, I rerolled literally every single item. My raging set gives 25%, shamrock helm 20%, daily blessing 20%, thrax 30%, greedy ring 20%, amber brew 7%; this adds up to 122% reroll/luck. How would I not reroll every single item I drop? It’s even weirder because the one mythic item I did drop, I rerolled an elite into the mythic, so why didn’t this happen for the rest of the elites I dropped with no reroll?

Another question I have is are there any prizes for leaderboard winners? I couldn’t find anything pertaining to this on the original xmas event post.