Gene, was your mozzarella fresh mozzarella? If so, it easily could have contributed to the runniness. I trust Scott’s experience with the Galbani WM. Many store bought ricottas are stiff at refrigerator temp, loose at room temp, and who knows once baked. It certainly can’t hurt to drain it for a couple hours or overnight — if anything drains off, it’s not something you wanted in your calzone anyway.
When I make ricotta, it actually comes out on the dry side but can take on a creamier texture by stirring it briefly after it has drained well (45-60 min) in a strainer lined with cheese cloth or a piece of an old, clean, t-shirt in a pinch. I have used it in lasagna (long bake time) with great results but have not made calzone with it.