Sacrificing on neutral altar doesn't update alignment on screen
You must press "redraw screen" in order to see whether you went to N=.
This bug has been around forever, and noticed that it's still there in R69. When you sacrifice on a neutral altar, your alignment goes towards N=. But especially when you are N+ or N-, the alignment on screen does not update. You must use the Ctrl+r function to redraw screen to see if you went to N=.
It's quite nasty when you are going towards a precrowning and end up crowned instead.