Don't know if it's worth the aggravation for me to bother with Ford.
Sort of like the 3 piece spark plug issue. Real stupid flaws on an otherwise great truck. I've got the bubbling tailgate problem on my '05. In the northeast where I live, I can walk up to 7 out of 10, 2nd gen's and they will have it. The amazing thing is that some bodyshops that I talked to would rather replace the whole tailgate than deal with it. Ouch! What's happening is that the gate is made of aluminum, like the hood. When you have two dissimilar metals in the kind of environment I'm in, and with the poor prep that others have mentioned, you get electrolysis.
When I can, I'll fix it myself so I know it won't happen again. Catalyst primer needs to be used. Where the license plate light brow attaches to the tailgate, fasteners, sealers and paints should be a type used to isolate the steel and aluminum to prevent this from happening again.