Not trying to start up the catch can discussion again but I found an interesting bit of information regarding the 2018 Ecoboost engine changes.
If I am reading the info correctly it appears that for is adding port fuel injection to the DI on the new motors. Maybe the do realize a carbon build up problem with the motors. Maybe its something else who knows.
Sorry for the double post I tried to delete the first one with no luck.

 

If I am not mistaken, my 2017 3.5l EcoBoost has port fuel injection in addition to DI.

 

What's more interesting is the new dual injection strategy is to use port injection most of the time. It will switch to DI when the engine is under load.