According to "Las Vegas rules", a cancelled game reducedsthe number of teaser legs by one. If you now have a one-leg teaser, the teaser is no action, even if the one remaining teaser leg lost.
Any book that grades a loss/no action teaser as a loss is wrong. Realize, a cancelled game is NOT a tie. Some books provide that a "tie and a loss" on a teaser loses. Unless the book specifically states that "a no action game is treated as a tie", AND "a tie and a loss is a loss", they need to grade that play as a no-action.