I read somewhere that DF1KY ruling was reversed, is it true? Does it blanks the effect along with its source and "negates" it or not?

See Omni FAQ. Antigoth's word is law.

Ninjazanus said:

What he said.

http://www.fantasyflightgames.com/edge_foros_discusion.asp?efid=30&efcid=5&efidt=167756

I just want to say, to add consistency to the current ruling, that kunai went to momentum face down as cost, but its effect obviously still took place, even without a text to refer to.