While my dock "auto-hide" is enabled when, in full-screen app, if I put the pointer to the very bottom, the dock won't show up. Unless, and this might be a bug, I move my mouse horizontally and it reaches and already opened app. Sounds weird but I don't understand
I was a bit stumped by this, but actually I think there is an explicit procedure.
When in full-screen mode, move the cursor to the bottom of the screen; then drag down with one finger. The dock will then appear.
It appears it doesn't matter where you do this (which application icon you happen to hovering over) as far as I can see.
It has to be also with the speed you use. If you move the mouse slower, when it reaches the bottom the dock will show up. I think is intentional, but I don't like it.
I was having this problem too. I tried moving the mouse down to the bottom of the screen and then pulling down again and that worked. Don't ask me why it has to be this complicated, I think its a bug. Hope This is Helpful