Does it look like it is going down all the way when you close it. If it isn't, It don't let you slide back. I say this cause my gen1 sticks alot both ways. In other words if I have it slid back and close it, it doesn't always make it to the closed position. I have to push the button several times. Same if I'm in the vented position, It'll stick closing. Kinda like your discribing.