Is this a bug?

I made progression on Avacyn’s madness earlier today and got a EMN booster pack.

I looked at the percentage for the pack since the pack is so relatively rare.

The chance of getting a particular rarity was as follows:
0,00% common
100,00% uncommon
1,40% rare
32,52% mythic
0,00% MP

This seems quite odd compared to other packs, so I wonder if this is correct.

If I remember rightly it was a small expansion set with no common cards in it- not sure why the rare % is so low tho- maybe there weren’t very many in that subset

Correct, Eldritch Moon, Oath of the Gatewatch, and Aether Revolt were all originally added into the packs of the block they were a part of, and no common rarity cards were added for any of those three sets. Additionally, masterpieces weren’t a thing until Kaladesh, so there wouldn’t be any in the Eldritch Moon packs either.

The loot chance for rare and mythic rare does seem reversed, however.

I’d say a majority of the peeps in my coalition who reported in reported pulling a rare, myself included. No way the 1.4 is correct. Mythic percentage seems right on though, gonna be a lot more piggies flying around after this event. Ohhh boy!