On Insert 3 make sure it isn't feeding into the master either, but is feeding into Insert 2.
On Insert 2 insert the Fruity Limiter and make sure this insert is going out the Master. Insert 1 feeding to Inserts 2 & 3, but not being sent to the Master. How this works is to mult out the vocal track where you have the dry vocal itself being sent to two inserts e.g. There are a few ways to build a de-esser in FL.
