I noticed that if you select fewer unit, it takes less time to start moving. When you move unit to rally point, eventually they sort of overlap( with those squares represents space occupied by the unit.) So when that happens, you drag and select all trying to move, it will take forever(eh..like 5~10 seconds), before they start moving. But if you select the outer ring unit and click, they start moving faster and you can issue order to larger group of unit like that. It's not as broken as stuck units, but still need to take account of.
