The die was in the VLDS when your coin was struck. The die wear is making a distortion at the tops of the devices, towards the rim. Here is something that will help with the die wear on the Memorial reverses:

Note the lowest image. That is the dies state, when your coin was struck.
Here is a Wheat cent obverse that the same thing is happening:


Note the lowest image. That is the dies state, when your coin was struck.
Here is a Wheat cent obverse that the same thing is happening:

























