I currently have 15 in inventory, have used all the ones I can so far, on new discovered shouts. But the dragons keep on coming, like insane lemmings. Really big, winged lemmings. So I kill them. And the souls pile up. Thought nothing of it, until just now, when I killed another blood dragon in the rift tundra area, and it did not disintegrate and give me it's soul after I killed it. Just lays there... nothing. Kinda like my ex.
Is there a limit to how many unused dragon souls you can have on you at any time? Or is this just a bug? I'm on PC.
Edit: I restarted from save and did the fight again, same thing, exactly. No soul.