After I search for "foo" by doing "?foo", I can search forward by "n" or backward by "N", however sometimes the n/N directions are flipped in the middle of search. If I restart Vim, it's OK again. What key sequence may I have pressed to cause this? How to revert back to normal mode?
I don't recall that I ever ran into this in old Vi.
EDIT: it's not the Caps Lock key. Thanks for the suggestion though.