Can a model who is Targeted enter Camouflaged State or is Targeted intended to prevent a model from entering Camouflaged State? If so does Targeted apply the +3 mod for an enemy model which attempts to Discover?
Nothing in Targetted prevents entering the Camouflaged state. The Camouflaged Trooper remains in the Targeted State so Targeted will continue to apply, however Targeted has no effect on Discover: "Any Trooper declaring a BS Attack, Hacking Program or Comms Attack against a Trooper in the Targeted State gains a +3 MOD to the Attribute used to perform that Attack." You can't declare Attacks against Troopers in a Marker state. So, realistically there's no interaction: Discover + BS Attack is kinda an exception, but not really.
Discover says If the user passes a Normal WIP Roll, applying the same MODs as in a BS Attack (Cover, Range, Mimetism...), the target Marker is removed, and must be replaced with the actual Trooper Model, or Weapon or Equipment Token.And I note that Targeted doesn't seem to require an attack to be declared, but the criteria is a BS Attack. The question becomes if this is a MOD for BS Attack or if this is a separate effect that happens because of BS Attack declaration. I'm inclined to see this as a MOD to BS Attack and in such case it would apply to Discover - so when trying to Discover a Holoecho/Holomask I think it's pretty clear you get the +3. Next step is what I am less certain of and that is if Targeted applies to the Marker when it is applied to the Trooper under the Marker...
Reading that states applied to the Trooper don't also apply to the Marker is weird. Fair point about it being a BS Attack MOD and those being applied to Discover.