If link is charging his sword, and side steps into an armos. It doesn't activate, simple enough. If you walk into it normally it activates however. Not sure if you touch it with links back though.
Also, the Armos/Grave NES bug fix rule was on when I discovered this. And I'm using 8-way movement, which has it's own issues.
Do you mean hitting the armos from the side or do you mean hitting the armos while not facing it?
Hitting it while not facing it.
Edit: Works with graves as well, well their bugged as well.
Also, you can not activate "but should" armos/graves two ways that I know of. Diagonal walking along them and holding the swordas if you were going to do a spin attack.