Account-level rubrics are shared between courses so that each course does not have to recreate them. They are attached to / used by some assignment. When that happens, they show up on the rubrics page like any other rubric.
You can get a list of the account rubrics by going to an assignment and clicking Find Rubric. Then scroll through to find the name of your account. Mine is at the bottom, but that's because I added a script that sorts them.
A quicker way would be to go to your rubrics page and click on one of the two rubrics that don't show up when you try to copy them. You are now viewing a rubric.
The location (URL) at the top of the browser should have a pathname of something like this (but with different numbers):
/courses/4014893/rubrics/560115
Keep the scheme and hostname, but modify the pathname to add a /api/v1 to the beginning. It now looks like this:
/api/v1/courses/4014893/rubrics/560115
When you hit enter, you'll get some computer code called JSON (Firefox may organize it for you, but Chrome runs it all together).
Near the top is an id, context_id, and context_type.
{"id":560115,"context_id":97773,"context_type":"Account","data":
It's the context_type you're looking for. If it says Account, then it's an account rubric, created by someone else but used in your class and it won't copy over to the new class during an import. If it's Course, then it's a course rubric and should be showing up.