This is based on rule 18.2.4.5: “a player intentionally bobbles, fumbles or delays the disc to themselves, for the sole
purpose of moving in a specific direction.”
In the situation we are describing, the “first touch” to block the disc is not relevant to 18.2.4.5. The “second touch” is an intentional tipping off the disc, but it’s not to themselves, so again, 18.2.4.5 does not apply. However if the “second touch” as followed by a “third touch” by the same player, then 18.2.4.5 would apply.
Hope that helps.