Black outline on certain Pocket Interfaces has more pixels than it should

On some interfaces on the pocket ui there is a black outline around the interface that seems "sharper" and has more pixels than what is intended. This seems to happens mostly on interfaces that don't cover the entire screen and it affect alot of blocks. Here is a image of it on the furnace interface:

Steps to Reproduce:
1. Pick a functional block like the furnace
2. Open the interface
3. Look at its corners

Observed Results:
The black outline make the border of the interface look more square (in a bad way).

Expected Results:
It probably should not look like this.