Greetings from Barcelona. What you perceive as a fault in service with regard to dessert and coffee really isn't a fault at all, but rather is merely a difference in American vs. European cultural and eating practices.
In North America, you tend to be served dessert and coffee at the same time. In Europe, that is a no-no -- first you have dessert, and then coffee, after-dinner liqueurs, etc. follow as the complete end to the meal.
Silversea provides European-style dining service and has one of the highest percentages of European vs. North American clientele in the industry.
That may be why you perceived a slight fault in service. For us, it would have been a fault to serve dessert and coffee at the same time.
Enjoy your cruise -- we love your reports.