so I have gotten to a point where I am finding more than 1 dragon (usually 2) per encounter. I will kill one and absorb the soul, and then soon after I kill the second one but the dragon does not burn up and I don't absorb the soul. it just sits there rotting slowly like everything else. I am able to loot the dragon corpse, but, no soul.

its not a game breaker, I just wanted to mention it. maybe they can look into it and fix it on a latter patch.

There are times when a dragon will not give you a soul. This happens with respawning dragons.

If you kill a dragon and it doesn't give you a soul or burn up, then it's just a generic respawn of a dragon you've previously killed.

I think Beth did it this way for 2 reasons. Because they wanted a constant dragon count in the world so they don't run dry, and to prevent "soul farming".