Random screens are part of the CBP normal and GE experience. GE members are trusted travelers but are still subject to random screenings. You might have just hit a time of day or a flight where not permissible foods often come from. Cheeses from France & sliced meats from Italy are common catches for CBP. Agents may be told to review a certain number of travelers during a day.

Two flights is a small sample size but still understandably annoying. If it continues you could apply for a redress number hoping this removes any potential flags that may have been added to your file but this sounds like random selection with not so great luck to me.