Unable to give an armor stand (item) to an armor stand

Summary:
Unable to give armor stand (item) to an armor stand. This can only be done with the /replaceitem command.

Steps to reproduce:

1.  Place an armor stand.
2.  Try give an armor stand (item) to an armor stand.

Observed results:
You cannot give an Armor Stand (item) to an Armor Stand.

Expected results:
You can give an Armor Stand (item) to an Armor Stand (like any other item).