It's a simple problem to solve. All Ford has to do is put a electric purge blow-off valve on the intercooler. That and a water sensor in the intercooler and a little software fix. Done.
But as usual, the manufacture wants to cheap out and leave the customer hanging.
These things must have a lot of water hanging out in the tank of the intercooler because I use water injection on all of my turbo engines and never had a misfire when using it. And I inject A LOT of water.
BTW the reason you don't see a misfire in a turbo diesel engine is because there is no stoichiometry on a diesel like there is on a gasoline engine. On a lean engine like all DI are, even a small amount of water will cause a misfire.