I have seen games where a flag was picked up and waved off after a conference between the refs. Could they not do the same thing after the review overturns the targeting foul?
I'm guessing a bit here, but I think it works like this.
Targeting is (currently) a 2-step call:
1. Flag is thrown when defenseless player is hit. Not reviewable, ref's discretion, 15-yard penalty.
2. Review examines closely to determine whether head-to-head contact was made by defender (using helmet as weapon). Player is suspended from play if guilty.