What is going on with collector numbers

Sorting my draft chaff from the last year, and i noticed something odd about collector numbers in Duskmorn. There are cards that have 2 different collector numbers, with no difference I can see. Here is the 2 versions of Grand Entryway // Elegant Rotunda, which was the first card i noticed it on, one is number 15, and the other is 287, and i have no idea why. They appear identical, neither is foil or anything. So what's up with this, why the 2 different numbers?

Sorting my draft chaff from the last year, and i noticed something odd about collector numbers in Duskmorn. There are cards that have 2 different collector numbers, with no difference I can see. Here is the 2 versions of Grand Entryway // Elegant Rotunda, which was the first card i noticed it on, one is number 15, and the other is 287, and i have no idea why. They appear identical, neither is foil or anything. So what's up with this, why the 2 different numbers?