2020 D Penny DD Or MD?

Well it is not a doubled die, but it is Machine Doubling. Machine Doubling is caused by the machine after the strike. On a doubled die, the die is doubled, striking a doubled die coin. How to tell the difference? On Machine Doubling, the size of the devices are normal. MD reduces an outside edge of the normal devices. Creating a coin with devices even smaller than normal. Note your mistake. When you look for a doubled die, you should check not the outside edges of the devices, but the centers of the devices for a widening. On the single squeeze dies, the devices on these devices Will look enlarged. I like them to looking like over inflated bicycle tubes. Here are a few examples:
Normal device on top image, DDO on the lower image:

Note how enlarged and distorted these devices look. I like to show them side by side so you can spot the difference without having to move your eyes from one location to another, as they are right in front of you.



These are all different dies for that year. Again, note how they look distorted?
This one is marked normal, but both are doubled dies. Note the distorted devices on both images and the smaller centers?

Something else to not on doubled dies, it the centers of closed devices will look smaller than normal as they enlarging is on the whole centers of the devices and make the center areas smaller.

On this one the devices are not enlarged as much, but note the white arrows showing the off set of the devices. This is called notching. See the notches on the corners?
Other times again they look like over inflated tubes:

Hope this helps you to see the differences.
Welcome to the forum. I'll hang out the welcome sign:

Thanks for the help and the pictures Coop. This is very helpful.