I have a working theory about the dumps, at least kind of working in my case, I need more data to confirm but it kind of worked this morning. Yesterday I wrote about it in another thread, I exercise a lot, my energy demands are quite high and metabolic rate is way up. Couple of weeks ago I completely cut carbs for breakfast, and my fbg started climbing up, day by day, higher and higher. Liver just kept dumping and dumping, until lunch, when I had some carbs. Yesterday, my fbg was 6.8, had protein and fats only breakfast and 2 hrs postprandial was 7.5, by lunch time it climbed all the way to 8. It started slowly going down after carby lunch (well, carbs from veggies etc.). I ate 200 grams of strawberries and blueberries with some Skyr yogurt in the afternoon, and then some more strawberries for dessert after dinner. This morning my fbg was 5.8, for breakfast I had carbs, 2 slices of wholemeal rye bread and some cottage cheese, 2 hr postprandial reading of 6.3, before lunch 6.1. This is much better than yesterday when I had no carbs till lunch.
My theory is that (in my case) due to higher energy demands of (my) body, protein and fats breakfast does not stop my liver from dumping, either due to my body not recognizing it as sufficient source of energy or that due to gluconeogenesis being a relatively slow process (it takes hours to convert protein and fat to glucose) and the liver, anticipating large energy demand, just keeps dumping and dumping until it gets a signal to stop when some carbs are eaten.
I will be testing this theory in the next few days