Read my post (#9). This is exactly what I said. Part of the problem is worn sprocket, but even if perfect the inner plates will touch the tips of the teeth when coming from an angle.

You have 5 choices besides replacing the worn freewheel. (which won't totally solve the problem)

1- file or grind more entry bevel on the sides of the teeth, so the points slide into the chain more smoothly. Look at your chainrings to see the difference. If you go this route, make sure to file on the offending side of the sprocket.

2- use a chain with more bellmouth or bevel on the inside of the inner plates, which act as a funnel to guide the teeth in smoothly

3- use a quality shocking absorbing oil, like Chain-L which doesn't actually change anything, but dampens the tiny impacts quieting the chain. (sorry for the cheap plug, but it's appropriate here)

4- go single speed, eliminating non-aligned sprockets entirely

5- live with it, it's a characteristic of derailleur bikes and will never go away entirely.